《Nature》目录要览：2009-12-03出版
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《Nature》目录要览：2009-12-03出版
封面故事：脱落酸的晶体结构
A gate–latch–lock mechanism for hormone signalling by abscisic acid
receptors
脱落酸（ABA）是一种主要植物激素，其作用是保护植物不受干旱和低温等压力影响，
并且在气孔打开和种子休眠等日常响应中发挥作用。在ABA通道中作为受体而引人注目
的是PYR/PYL/RCAR家族的蛋白以及2-型磷酸酶ABI1、ABI2 和PP2C，它们抑制ABA信号作
用。现在，三个小组报告了ABA在非结合状态及在包括PYL2-ABA-PP2C和PYL1-ABA-ABI1
在内的不同复合物中的晶体结构。这些结构表明，PYL/ABA生成一个与PP2C 和ABI1相结
合的疏水穴，同时结合生化研究，这些结构还为ABA信号作用指出了一个机制
（Articles pp. 602, 609; Letter p. 665）。Jian-Kang Zhu及其同事在试管中重构
了ABA信号通道（这对植物激素来说是第一次），并在活体中对关键观测结果进行了验
证（Letter p. 660）。正如Laura Sheard 和Ning Zheng在News & Views文章中所解释
的那样，ABA的受体的发现是人们所期待的，以ABA信号作用为目标进行研究对农业化学
应用来说是很有希望的。 本期封面所示为一株在抗击干旱的沙漠报春花。封面图片提
供：Alan Kearney/Getty Images。
细胞系的强行改变（Enforced cell lineage change）
Forcing cells to change lineages
虽然多细胞生物的很多不同细胞类型一旦分化之后保持稳定对这些生物的成功很重要，
但在通过将体细胞暴露于一种所谓的“转录因子鸡尾酒”来生成诱导多能干（iPS）细
胞方面所取得的进展却凸显了这样一个事实：几乎任何细胞都有被重新编程的潜力。这
便提出了一个问题；细胞类型之间的相互转换是因生理原因出现的，还是在疾病背景下
出现的？Thomas Graf 和Tariq Enver利用来自血液细胞系的例子来说明转录因子转分
化（transdifferentiation）的原理，他们得出的结论是，转分化从根本上来说是一个
与分化类似、与iPS重新编程不同的过程。他们假设，一个细胞类型向另一个的转化可
以作为一个正常发育过程发生；同时他们还猜测了在再生医学中对细胞系进行强行重新
编程的前景。（Review p. 587）
生成iPS细胞的快速方法（Fast track to iPS cells）
Direct cell reprogramming is a stochastic process amenable to acceleration
Rudolf Jaenisch及其同事发现，通过Oct4、Sox2、Klf4和c-Myc转录因子的过度表达来
对体细胞直接进行重新编程以生成诱导多能干（iPS）细胞，是一个连续的随机过程，
在该过程中几乎所有供体细胞最终都将产生iPS细胞。重要的是，因为iPS细胞的生成相
对来说仍然比较慢，效率比较低，所以研究人员提出了加快这一过程的两种方法：一是
通过加快细胞分裂的速度；二是通过独立于细胞分裂速度的Nanog过度表达。（Article
p. 595）
泛素链形成的机制研究（Extending the ubiquitin chain）
Detection of sequential polyubiquitylation on a millisecond timescale
泛素链向蛋白质上的结合是一个重要的翻译后修饰过程，控制蛋白质的稳定性、定位和
活性。在这个过程中，一系列酶（E1、E2和E3）调控泛素链的组合体，而且当正确的泛
素化发生之后，一个冗余的或受损的蛋白就会被蛋白酶体破坏掉。泛素链形成的机制尚
不清楚。Ray Deshaies及其同事利用生物化学和计算方法以毫秒分辨率对泛素链的形成
进行了研究。他们的发现支持这样的假设：泛素链是通过单个泛素链分子的依序转移在
基质上构建的。这项工作应有助于寻找以泛素化酶为目标的治疗方法。（Article p.
615; News & Views）
“天鹅座 X-3”：一个有耀斑的微类星体（Cygnus X-3: a microquasar with flare）
Extreme particle acceleration in the microquasar Cygnus X-3
银河系微类星体是双星体系，其中一个中子星或恒星质量黑洞从一个伴星那里吸积气
体。它们能将粒子加速到相对论能量，并发出射电耀斑，但我们并不知道喷射激发
（jet energization）的机制。在2007年年中和2009年年中之间对“天鹅座”区域所做
的一次观测，探测到四次较大的伽马射线耀斑形成事件，能量超过100 MeV，每次事件
持续1到2天时间，这些耀斑是从微类星体“天鹅座 X-3”发出的。在这些伽马射线耀斑
与射电和X-射线的过渡性光谱状态之间有一个明显的时间关联模式。粒子加速对其中两
个耀斑来说发生在射电喷射之前几天时间，说明喷射流的形成涉及高能粒子的生成。
（Letter p. 620）
我们所在宇宙区域可能存在巨大恒星（A massive star’s exit）
Supernova 2007bi as a pair-instability explosion
太阳之类的恒星以白矮星的形式结束它们的恒星生命。理论预测，质量超过140个太阳
质量的恒星有一个不同的命运（如果它们存在的话；它们在银河系中是不存在的）。当
它们演化到拥有氧核的阶段时，支撑压力的光子会转变成电子-正电子对，吸收能量，
使核心坍缩而产生一个“对不稳定性”（pair instability）超新星。对超新星2007bi
（一个附近矮星系中的一次发光事件）的光谱和光曲线所做的分析，为这样一种爆炸提
供了证据。超新星 2007bi的前身预计曾有一个超过100个太阳质量的核心。计算表明，
曾发生了一次爆炸，这次爆炸产生了超过三个太阳质量的放射性镍-56，这与我们从一
个巨大氧核会预料到的结果是一致的。这一发现意味着，在我们所在的宇宙区域中有质
量极为巨大的恒星，它们有可能为天文学家提供对那种也许曾经在早期宇宙中居支配地
位的恒星类型进行仔细观测的机会。（Letter p. 624; News & Views）
为超冷中性原子合成高强磁场的新方法（Magnetic mimic）
Synthetic magnetic fields for ultracold neutral atoms
原子玻色-爱因斯坦凝聚态（BEC）可被用来研究发生在比较复杂体系中的多体现象（如
超导性）。然而，很多神秘现象是对一个磁场中的带电粒子发生的，而BEC是中性的。
这个缺憾可通过转动中性系统以生成一个合成磁场来避免，但这样的磁场强度是有限
的。Lin等人报告了通过光学手段为超冷中性原子合成磁场的方法，该方法不受转动操
作的局限性的影响。该方法有可能产生达到量子霍尔效应范畴所需的高强磁场，这将使
拓扑量子计算的研究成为可能。（Letter p. 628; News & Views）
太阳辐射对季风的影响（Solar influence on monsoons）
Half-precessional dynamics of monsoon rainfall near the East African Equator
外部气候影响（如太阳辐射或日射）在不同区域产生不同反应。我们有大量来自高纬度
和低纬度地区的记录，可以利用这些记录来评估日射与气候变化之间的关系。但热带记
录却要少得多，而来自“热带辐合区”（Intertropical Convergence Zone）（该区域
产生干湿季节交替的季风气候）所在路径之区域的记录还要更少。Verschuren等人找到
了这样一个记录，并对Challa湖（乞力马扎罗山山坡上的一个火山口湖）2.5万年沉积
序列中水文变化的相关指标进行了分析。他们发现，东非的季风降雨以大约1.15万年的
周期变化，与由轨道控制的太阳辐射力相一致。（Letter p. 637）
Foxa2的减肥潜力（Foxa2 shows antiobesity potential）
Regulation of adaptive behaviour during fasting by hypothalamic Foxa2
胰岛素调控对于节食和进食的代谢和行为反应的一个新颖机制已被发现。在节食期间，
神经肽阿立新（亦称“苯基二氢喹唑啉”）和MCH（黑色素浓缩激素）在“下丘脑外侧
区”（大脑中传统中被认为是“进食中心”的区域）释放，在那里它们诱导有动机的行
为和刺激食物摄取。用小鼠所做的研究表明，阿立新和MCH的表达由转录因子Foxa2调
控。进食之后，胰岛素信号作用会使Foxa2无效，使阿立新和MCH的生成停止。Foxa2的
活性被永久打开的小鼠有更多的阿立新和MCH，吃的更多，身体更活泼，对胰岛素的敏
感度也有所提高。打开肥胖小鼠身体中的Foxa2，会增加身体中瘦肉含量，减少脂肪含
量。因此，通过药理手段阻断Foxa2的磷酸化，可能会增强身体活动水平，提高总体健
康状况。（Letter p. 646）
与慢性疼痛有关的传感神经元（A touch of pain）
Injury-induced mechanical hypersensitivity requires C-low threshold
mechanoreceptors
皮肤在受伤、发炎或日灼后会变得高度敏感，即便是最轻的碰触也会引起强烈疼痛。这
种疼痛通常会很快消失，但在某些情况下它则会持久存在，造成难以治愈的、让人痛苦
不堪的疼痛，部分原因是其中所涉及的神经回路的身份没有确定。现在研究人员发现，
新的一类初级传感神经元与这些慢性疼痛综合症有关。缺少非传统“囊泡谷氨酸转运
体” VGLUT3的突变小鼠，对强烈机械性疼痛敏感性降低，对受伤之后的轻触不再高度
敏感。背根神经节中的VGLUT3+神经元是无髓低阈限机械受体，它们被发现与人类的愉
快触觉有关，而在受伤后的高度敏感期间它们传递的似乎是一种痛感。这一发现为实验
和治疗干预提供了新途径。（Letter p. 651; News & Views）
引人注目的环境RNA（Remarkable environmental RNAs）
Exceptional structured noncoding RNAs revealed by bacterial metagenome
analysis
对从由海水样品提取出的物质获得的环境DNA 和RNA序列所做的计算分析，显示了丰富
的细菌非编码RNA（ncRNA）的存在，它们在大小和复杂性上很像大型核糖酶。人们特别
感兴趣的是两种新发现的RNA，被称为GOLLD 和 HEARO，它们是迄今所发现的最大、最
复杂的RNA之一。这些发现表明，在水中、土壤中和尚未探索的其他环境中，存在很多
有待发现的具有超大尺寸、复杂结构或其他特别之处的RNA。（Letter p. 656）
----------------------
NEWS AND VIEWS
----------------------
Plant biology: Signal advance for abscisic acid pp575-576
The hunt for the receptor for abscisic acid, initially marked by false
starts and lingering doubts, has met with success. Converging studies
now reveal the details of how this plant hormone transmits its message.
Laura B. Sheard and Ning Zheng
doi:10.1038/462575a
http://www.nature.com/nature/journal/v462/n7273/full/462575a.html
Biological chemistry: Dehydrated but unharmed pp576-577
The weakest interactions of protein complexes are thought to be lost when
such assemblies are removed from their natural, watery environments. Not
so, reveals a study in the vacuum chamber of a mass spectrometer.
Justin L. P. Benesch and Carol V. Robinson
doi:10.1038/462576a
http://www.nature.com/nature/journal/v462/n7273/full/462576a.html
50 & 100 years ago p577
doi:10.1038/462577a
http://www.nature.com/nature/journal/v462/n7273/full/462577a.html
Astrophysics: Different stellar demise pp579-580
A decades-old theory of stellar evolution - that the most massive stars
end their life in a peculiar type of explosion termed a pair-instability
supernova - finally seems to have been confirmed by observations.
Norbert Langer
doi:10.1038/462579a
http://www.nature.com/nature/journal/v462/n7273/full/462579a.html
Neuroscience: Unbearable lightness of touch pp580-581
Following inflammation or nerve injury, stimuli that are normally
perceived as innocuous can evoke persistent pain. A population of
neurons that contributes to this syndrome has now been identified.
Liam J. Drew and Amy B. MacDermott
doi:10.1038/462580a
http://www.nature.com/nature/journal/v462/n7273/full/462580a.html
Structural biology: Steps in the right direction pp581-583
The ring-shaped helicase enzyme Rho moves along RNA using ATP as an
energy source. Coordinating ATP hydrolysis with nucleic-acid binding
seems to determine the direction and mechanism of helicase movement.
Smita S. Patel
doi:10.1038/462581a
http://www.nature.com/nature/journal/v462/n7273/full/462581a.html
Atomic physics: Neutral atoms put in charge pp584-585
An elegant experiment shows that atoms subjected to a pair of laser
beams can behave like electrons in a magnetic field, as demonstrated
by the appearance of quantized vortices in a neutral superfluid.
Martin Zwierlein
doi:10.1038/462584a
http://www.nature.com/nature/journal/v462/n7273/full/462584a.html
Cell biology: Stairway to the proteasome pp585-586
The study of fast and intricate enzyme reactions requires methods that
have the speed and sophistication to match. Such an approach reveals
the way in which proteins are tagged with ubiquitin for destruction.
Malavika Raman and J. Wade Harper
doi:10.1038/462585a
http://www.nature.com/nature/journal/v462/n7273/full/462585a.html
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REVIEW
----------------------
Forcing cells to change lineages pp587-594
Thomas Graf and Tariq Enver
doi:10.1038/nature08533
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08533.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08533.html
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ARTICLES
----------------------
Direct cell reprogramming is a stochastic process amenable to acceleration
pp595-601
Overexpression of certain transcription factors can reprogram somatic cells
into induced pluripotent stem (iPS) cells; however, only a minority of donor
somatic cells can be reprogrammed to pluripotency. Here, this reprogramming
is shown to be a continuous stochastic process where almost all mouse donor
cells eventually give rise to iPS cells on continued growth and
transcription
factor expression; changing certain parameters results in accelerated iPS
cell formation.
Jacob Hanna et al.
doi:10.1038/nature08592
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08592.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08592.html
A gate-latch-lock mechanism for hormone signalling by abscisic acid
receptors
pp602-608
The plant hormone abscisic acid (ABA) is a regulator of plant growth,
development and responses to environmental stresses. Recently, the
PYR/PYL/RCAR family of START proteins was found to bind ABA and mediate
inactivation of downstream effectors. The crystal structures of apo and
ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex is now r
eported and analysed, revealing a gate-latch-lock mechanism underlying ABA
signalling.
Karsten Melcher et al.
doi:10.1038/nature08613
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08613.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08613.html
Structural basis of abscisic acid signalling pp609-614
The plant hormone abscisic acid (ABA) is a regulator of plant growth,
development and responses to environmental stresses. Within plants, the
PYR/PYL/RCAR family of START proteins receives ABA to inhibit the
phosphatase
activity of the group-A protein phophatases 2C (PP2Cs). Here, the crystal
structures of ABA bound to its receptor PYL1 and a complex formed between
ABA, PYL1 and the PP2C protein ABI1 are presented, shedding light on the
structural basis of ABA signalling.
Ken-ichi Miyazono et al.
doi:10.1038/nature08583
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08583.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08583.html
Detection of sequential polyubiquitylation on a millisecond timescale
pp615-619
Conjugation of ubiquitin chains onto proteins is an important
post-translational
modification that regulates the stability, localization and activity of
substrate proteins. A series of enzymes known as E1, E2 and E3 mediate
assembly of ubiquitin chains but the pathway remains unclear. Theoretical
and experimental methodologies are now introduced to study the formation
of ubiquitin chains at millisecond time resolution, demonstrating that
substrate polyubiquitylation proceeds sequentially.
Nathan W. Pierce, Gary Kleiger, Shu-ou Shan and Raymond J. Deshaies
doi:10.1038/nature08595
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08595.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08595.html
----------------------
LETTERS
----------------------
Extreme particle acceleration in the microquasar
Cygnus[thinsp]X-3 pp620-623
Super-massive black holes in active galaxies can accelerate particles to
relativistic energies, producing jets with associated [gamma]-ray emission.
Galactic 'microquasars' also produce relativistic jets; however, apart from
an isolated event detected in Cygnus X-1, there has hitherto been no
systematic
evidence for the acceleration of particles to gigaelectronvolt or higher
energies in a microquasar. Here, a report of four [gamma]-ray flares with
energies above 100 MeV from the microquasar Cygnus X-3 illuminates this
important problem.
M. Tavani et al.
doi:10.1038/nature08578
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08578.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08578.html
Supernova 2007bi as a pair-instability explosion pp624-627
Extremely massive stars with initial masses of more than 140 solar masses
end their lives when pressure-supporting photons turn into electron-positron
pairs, leading to a violent contraction that triggers a nuclear explosion,
unbinding the star in a pair-instability supernova. Here, the mass of the
exploding core of supernova SN 2007bi is estimated at around 100 solar
masses,
in which case theory unambiguously predicts a pair-instability supernova.
Further observations are well fitted by models of pair-instability
supernovae.
A. Gal-Yam et al.
doi:10.1038/nature08579
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08579.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08579.html
Synthetic magnetic fields for ultracold neutral atoms pp628-632
Atomic Bose-Einstein condensates can be used to study many-body phenomena
that occur in more complex material systems; however, the charge neutrality
of these systems prevents intriguing phenomena that occur for charged
particles
in a magnetic field. Rotation can be used to create a synthetic magnetic
field,
but such fields are of limited strength. An optically synthesized magnetic
field for ultracold neutral atoms that is not subject to the limitations of
rotating systems is now experimentally realized.
Y.-J. Lin et al.
doi:10.1038/nature08609
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08609.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08609.html
Controlling photonic structures using optical forces pp633-636
Optical forces can be used to manipulate small objects; for instance, in
optical tweezers. However, it is challenging to manipulate the optical
response of photonic structures using optical forces because of the large
forces that are required to induce appreciable changes in the geometry of
the structure. Here, a resonant structure made of silicon nitride is
demonstrated whose optical response can be efficiently statically controlled
using relatively weak attractive and repulsive optical forces.
Gustavo S. Wiederhecker, Long Chen, Alexander Gondarenko and Michal Lipson
doi:10.1038/nature08584
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08584.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08584.html
Half-precessional dynamics of monsoon rainfall near the East African Equator
pp637-641
Extensive records exist with which to assess the relationship between
external
climate forcings - such as changes in insolation - and climate variability
for
middle and high latitudes, but records from equatorial regions are
relatively
few, especially from regions experiencing the passage of the Intertropical
Convergence Zone. A continuous and well-resolved climate-proxy record of
hydrological variability during the past 25,000 years from equatorial East
Africa is now presented and analysed.
Dirk Verschuren et al.
doi:10.1038/nature08520
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08520.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08520.html
Common dependence on stress for the two fundamental laws of statistical
seismology pp642-645
The Gutenberg-Richter relation and the Omori-Utsu law, both power laws, are
two of the long-standing relationships of statistical seismology. Here,
aftershock sequences are described according to the faulting style of their
main shocks, showing that the time delay before the onset of the power-law
aftershock decay rate is on average shorter for thrust main shocks than for
normal fault earthquakes. These similar dependences on the faulting style
indicate that both the fundamental power laws are governed by the state of
stress.
Clement Narteau, Svetlana Byrdina, Peter Shebalin and Danijel Schorlemmer
doi:10.1038/nature08553
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08553.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08553.html
Regulation of adaptive behaviour during fasting by hypothalamic Foxa2
pp646-650
The lateral hypothalamic area is the 'feeding centre' in the brain. During
fasting, the neuropeptides orexin and melanin-concentrating hormone (MCH)
are
released in this area and stimulate food intake. The expression of orexin
and
MCH is now shown to be regulated by the transcription factor Foxa2, a
downstream target of insulin signalling. The results show that Foxa2 can
act as a metabolic sensor to integrate metabolic signals, adaptive behaviour
and physiological responses.
Jose P. Silva et al.
doi:10.1038/nature08589
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08589.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08589.html
Injury-induced mechanical hypersensitivity requires C-low threshold
mechanoreceptors pp651-655
Despite the contribution of mechanical pain to the morbidity associated with
inflammation and trauma, the primary sensory neurons that convey this
sensation have not been identified. Using knockout mice, the loss of the
low abundance vesicular glutamate transporter VGLUT3, expressed by a small
subset of peripheral sensory neurons projecting to areas implicated in
persistent pain caused by injury, is now shown to specifically impair
mechanical pain sensation.
Rebecca P. Seal et al.
doi:10.1038/nature08505
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08505.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08505.html
Exceptional structured noncoding RNAs revealed by bacterial metagenome
analysis pp656-659
Existing DNA sequence databases carry only a tiny fraction of the total
amount of DNA sequence space from bacterial species. Bioinformatics searches
of genomic DNA from bacteria commonly identify new noncoding RNAs (ncRNAs)
such as riboswitches. Here, an updated computational pipeline is used to
discover ncRNAs that rival the known large ribozymes in size and structural
complexity; other such RNAs probably remain to be discovered.
Zasha Weinberg, Jonathan Perreault, Michelle M. Meyer and Ronald R. Breaker
doi:10.1038/nature08586
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08586.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08586.html
In vitro reconstitution of an abscisic acid signalling pathway pp660-664
The plant hormone abscisic acid (ABA) is a regulator of plant growth,
development and responses to environmental stresses. Although several
proteins have been reported to function as ABA receptors and many more
are known to be involved in ABA signalling, the identities of ABA receptors
remain controversial and the mechanism of signalling unclear. ABA-mediated
signalling is now reconstituted in vitro, defining a minimal set of core
components of the pathway.
Hiroaki Fujii et al.
doi:10.1038/nature08599
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08599.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08599.html
The abscisic acid receptor PYR1 in complex with abscisic acid pp665-668
The plant hormone abscisic acid (ABA) has, among other things, a central
role in coordinating the adaptive response in situations of decreased water
availability. A family of intracellular ABA receptors, named PYR/PYL/RCAR,
has recently been identified. Here, the crystal structure of Arabidopsis
thaliana PYR1, which consists of a dimer in which one of the subunits is
bound to ABA, is presented.
Julia Santiago et al.
doi:10.1038/nature08591
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08591.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08591.html
Hidden alternative structures of proline isomerase essential for catalysis
pp669-673
X-ray crystallography and NMR spectroscopy are two powerful tools to
determine
the three-dimensional structures and characterize the dynamic properties of
proteins. The two methods are now combined to structurally unravel
interconverting
substrates of a human proline isomerase. Crystallographic approaches are
used
to define minor protein conformations and, combined with NMR analysis, to
show
how collective motions contribute to the catalytic power of an enzyme.
James S. Fraser et al.
doi:10.1038/nature08615
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08615.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08615.html
----------------------
ERRATA
----------------------
Remote triggering of fault-strength changes on the San Andreas fault at
Parkfield
p674
Taka'aki Taira, Paul G. Silver, Fenglin Niu and Robert M. Nadeau
doi:10.1038/nature08545
http://www.nature.com/nature/journal/v462/n7273/full/nature08545.html
El Nino in a changing climate p674
Sang-Wook Yeh et al.
doi:10.1038/nature08546
http://www.nature.com/nature/journal/v462/n7273/full/nature08546.html
Integration of neuronal clones in the radial cortical columns by EphA and
ephrin-A signalling p674
Masaaki Torii, Kazue Hashimoto-Torii, Pat Levitt and Pasko Rakic
doi:10.1038/nature08547
http://www.nature.com/nature/journal/v462/n7273/full/nature08547.html
----------------------
TECHNOLOGY FEATURES
----------------------
Microscopy: Ever-increasing resolution pp675-678
Overcoming the limitations of spatial and temporal resolution to image
within a cell is no easy feat. Kelly Rae Chi examines the latest
diffraction-busting technologies.
Kelly Rae Chi
doi:10.1038/462675a
http://www.nature.com/nature/journal/v462/n7273/full/462675a.html
Microscopy: Breaking the light barrier p676
doi:10.1038/462676a
http://www.nature.com/nature/journal/v462/n7273/full/462676a.html
Microscopy: Table of suppliers pp679-680
doi:10.1038/462679a
http://www.nature.com/nature/journal/v462/n7273/full/462679a.html
----------------------
FUTURES
----------------------
Press '1' to begin p688
The art of conversation.
Nye Joell Hardy
doi:10.1038/462688a
http://www.nature.com/nature/journal/v462/n7273/full/462688a.html
A gate–latch–lock mechanism for hormone signalling by abscisic acid
receptors
脱落酸（ABA）是一种主要植物激素，其作用是保护植物不受干旱和低温等压力影响，
并且在气孔打开和种子休眠等日常响应中发挥作用。在ABA通道中作为受体而引人注目
的是PYR/PYL/RCAR家族的蛋白以及2-型磷酸酶ABI1、ABI2 和PP2C，它们抑制ABA信号作
用。现在，三个小组报告了ABA在非结合状态及在包括PYL2-ABA-PP2C和PYL1-ABA-ABI1
在内的不同复合物中的晶体结构。这些结构表明，PYL/ABA生成一个与PP2C 和ABI1相结
合的疏水穴，同时结合生化研究，这些结构还为ABA信号作用指出了一个机制
（Articles pp. 602, 609; Letter p. 665）。Jian-Kang Zhu及其同事在试管中重构
了ABA信号通道（这对植物激素来说是第一次），并在活体中对关键观测结果进行了验
证（Letter p. 660）。正如Laura Sheard 和Ning Zheng在News & Views文章中所解释
的那样，ABA的受体的发现是人们所期待的，以ABA信号作用为目标进行研究对农业化学
应用来说是很有希望的。 本期封面所示为一株在抗击干旱的沙漠报春花。封面图片提
供：Alan Kearney/Getty Images。
细胞系的强行改变（Enforced cell lineage change）
Forcing cells to change lineages
虽然多细胞生物的很多不同细胞类型一旦分化之后保持稳定对这些生物的成功很重要，
但在通过将体细胞暴露于一种所谓的“转录因子鸡尾酒”来生成诱导多能干（iPS）细
胞方面所取得的进展却凸显了这样一个事实：几乎任何细胞都有被重新编程的潜力。这
便提出了一个问题；细胞类型之间的相互转换是因生理原因出现的，还是在疾病背景下
出现的？Thomas Graf 和Tariq Enver利用来自血液细胞系的例子来说明转录因子转分
化（transdifferentiation）的原理，他们得出的结论是，转分化从根本上来说是一个
与分化类似、与iPS重新编程不同的过程。他们假设，一个细胞类型向另一个的转化可
以作为一个正常发育过程发生；同时他们还猜测了在再生医学中对细胞系进行强行重新
编程的前景。（Review p. 587）
生成iPS细胞的快速方法（Fast track to iPS cells）
Direct cell reprogramming is a stochastic process amenable to acceleration
Rudolf Jaenisch及其同事发现，通过Oct4、Sox2、Klf4和c-Myc转录因子的过度表达来
对体细胞直接进行重新编程以生成诱导多能干（iPS）细胞，是一个连续的随机过程，
在该过程中几乎所有供体细胞最终都将产生iPS细胞。重要的是，因为iPS细胞的生成相
对来说仍然比较慢，效率比较低，所以研究人员提出了加快这一过程的两种方法：一是
通过加快细胞分裂的速度；二是通过独立于细胞分裂速度的Nanog过度表达。（Article
p. 595）
泛素链形成的机制研究（Extending the ubiquitin chain）
Detection of sequential polyubiquitylation on a millisecond timescale
泛素链向蛋白质上的结合是一个重要的翻译后修饰过程，控制蛋白质的稳定性、定位和
活性。在这个过程中，一系列酶（E1、E2和E3）调控泛素链的组合体，而且当正确的泛
素化发生之后，一个冗余的或受损的蛋白就会被蛋白酶体破坏掉。泛素链形成的机制尚
不清楚。Ray Deshaies及其同事利用生物化学和计算方法以毫秒分辨率对泛素链的形成
进行了研究。他们的发现支持这样的假设：泛素链是通过单个泛素链分子的依序转移在
基质上构建的。这项工作应有助于寻找以泛素化酶为目标的治疗方法。（Article p.
615; News & Views）
“天鹅座 X-3”：一个有耀斑的微类星体（Cygnus X-3: a microquasar with flare）
Extreme particle acceleration in the microquasar Cygnus X-3
银河系微类星体是双星体系，其中一个中子星或恒星质量黑洞从一个伴星那里吸积气
体。它们能将粒子加速到相对论能量，并发出射电耀斑，但我们并不知道喷射激发
（jet energization）的机制。在2007年年中和2009年年中之间对“天鹅座”区域所做
的一次观测，探测到四次较大的伽马射线耀斑形成事件，能量超过100 MeV，每次事件
持续1到2天时间，这些耀斑是从微类星体“天鹅座 X-3”发出的。在这些伽马射线耀斑
与射电和X-射线的过渡性光谱状态之间有一个明显的时间关联模式。粒子加速对其中两
个耀斑来说发生在射电喷射之前几天时间，说明喷射流的形成涉及高能粒子的生成。
（Letter p. 620）
我们所在宇宙区域可能存在巨大恒星（A massive star’s exit）
Supernova 2007bi as a pair-instability explosion
太阳之类的恒星以白矮星的形式结束它们的恒星生命。理论预测，质量超过140个太阳
质量的恒星有一个不同的命运（如果它们存在的话；它们在银河系中是不存在的）。当
它们演化到拥有氧核的阶段时，支撑压力的光子会转变成电子-正电子对，吸收能量，
使核心坍缩而产生一个“对不稳定性”（pair instability）超新星。对超新星2007bi
（一个附近矮星系中的一次发光事件）的光谱和光曲线所做的分析，为这样一种爆炸提
供了证据。超新星 2007bi的前身预计曾有一个超过100个太阳质量的核心。计算表明，
曾发生了一次爆炸，这次爆炸产生了超过三个太阳质量的放射性镍-56，这与我们从一
个巨大氧核会预料到的结果是一致的。这一发现意味着，在我们所在的宇宙区域中有质
量极为巨大的恒星，它们有可能为天文学家提供对那种也许曾经在早期宇宙中居支配地
位的恒星类型进行仔细观测的机会。（Letter p. 624; News & Views）
为超冷中性原子合成高强磁场的新方法（Magnetic mimic）
Synthetic magnetic fields for ultracold neutral atoms
原子玻色-爱因斯坦凝聚态（BEC）可被用来研究发生在比较复杂体系中的多体现象（如
超导性）。然而，很多神秘现象是对一个磁场中的带电粒子发生的，而BEC是中性的。
这个缺憾可通过转动中性系统以生成一个合成磁场来避免，但这样的磁场强度是有限
的。Lin等人报告了通过光学手段为超冷中性原子合成磁场的方法，该方法不受转动操
作的局限性的影响。该方法有可能产生达到量子霍尔效应范畴所需的高强磁场，这将使
拓扑量子计算的研究成为可能。（Letter p. 628; News & Views）
太阳辐射对季风的影响（Solar influence on monsoons）
Half-precessional dynamics of monsoon rainfall near the East African Equator
外部气候影响（如太阳辐射或日射）在不同区域产生不同反应。我们有大量来自高纬度
和低纬度地区的记录，可以利用这些记录来评估日射与气候变化之间的关系。但热带记
录却要少得多，而来自“热带辐合区”（Intertropical Convergence Zone）（该区域
产生干湿季节交替的季风气候）所在路径之区域的记录还要更少。Verschuren等人找到
了这样一个记录，并对Challa湖（乞力马扎罗山山坡上的一个火山口湖）2.5万年沉积
序列中水文变化的相关指标进行了分析。他们发现，东非的季风降雨以大约1.15万年的
周期变化，与由轨道控制的太阳辐射力相一致。（Letter p. 637）
Foxa2的减肥潜力（Foxa2 shows antiobesity potential）
Regulation of adaptive behaviour during fasting by hypothalamic Foxa2
胰岛素调控对于节食和进食的代谢和行为反应的一个新颖机制已被发现。在节食期间，
神经肽阿立新（亦称“苯基二氢喹唑啉”）和MCH（黑色素浓缩激素）在“下丘脑外侧
区”（大脑中传统中被认为是“进食中心”的区域）释放，在那里它们诱导有动机的行
为和刺激食物摄取。用小鼠所做的研究表明，阿立新和MCH的表达由转录因子Foxa2调
控。进食之后，胰岛素信号作用会使Foxa2无效，使阿立新和MCH的生成停止。Foxa2的
活性被永久打开的小鼠有更多的阿立新和MCH，吃的更多，身体更活泼，对胰岛素的敏
感度也有所提高。打开肥胖小鼠身体中的Foxa2，会增加身体中瘦肉含量，减少脂肪含
量。因此，通过药理手段阻断Foxa2的磷酸化，可能会增强身体活动水平，提高总体健
康状况。（Letter p. 646）
与慢性疼痛有关的传感神经元（A touch of pain）
Injury-induced mechanical hypersensitivity requires C-low threshold
mechanoreceptors
皮肤在受伤、发炎或日灼后会变得高度敏感，即便是最轻的碰触也会引起强烈疼痛。这
种疼痛通常会很快消失，但在某些情况下它则会持久存在，造成难以治愈的、让人痛苦
不堪的疼痛，部分原因是其中所涉及的神经回路的身份没有确定。现在研究人员发现，
新的一类初级传感神经元与这些慢性疼痛综合症有关。缺少非传统“囊泡谷氨酸转运
体” VGLUT3的突变小鼠，对强烈机械性疼痛敏感性降低，对受伤之后的轻触不再高度
敏感。背根神经节中的VGLUT3+神经元是无髓低阈限机械受体，它们被发现与人类的愉
快触觉有关，而在受伤后的高度敏感期间它们传递的似乎是一种痛感。这一发现为实验
和治疗干预提供了新途径。（Letter p. 651; News & Views）
引人注目的环境RNA（Remarkable environmental RNAs）
Exceptional structured noncoding RNAs revealed by bacterial metagenome
analysis
对从由海水样品提取出的物质获得的环境DNA 和RNA序列所做的计算分析，显示了丰富
的细菌非编码RNA（ncRNA）的存在，它们在大小和复杂性上很像大型核糖酶。人们特别
感兴趣的是两种新发现的RNA，被称为GOLLD 和 HEARO，它们是迄今所发现的最大、最
复杂的RNA之一。这些发现表明，在水中、土壤中和尚未探索的其他环境中，存在很多
有待发现的具有超大尺寸、复杂结构或其他特别之处的RNA。（Letter p. 656）
----------------------
NEWS AND VIEWS
----------------------
Plant biology: Signal advance for abscisic acid pp575-576
The hunt for the receptor for abscisic acid, initially marked by false
starts and lingering doubts, has met with success. Converging studies
now reveal the details of how this plant hormone transmits its message.
Laura B. Sheard and Ning Zheng
doi:10.1038/462575a
http://www.nature.com/nature/journal/v462/n7273/full/462575a.html
Biological chemistry: Dehydrated but unharmed pp576-577
The weakest interactions of protein complexes are thought to be lost when
such assemblies are removed from their natural, watery environments. Not
so, reveals a study in the vacuum chamber of a mass spectrometer.
Justin L. P. Benesch and Carol V. Robinson
doi:10.1038/462576a
http://www.nature.com/nature/journal/v462/n7273/full/462576a.html
50 & 100 years ago p577
doi:10.1038/462577a
http://www.nature.com/nature/journal/v462/n7273/full/462577a.html
Astrophysics: Different stellar demise pp579-580
A decades-old theory of stellar evolution - that the most massive stars
end their life in a peculiar type of explosion termed a pair-instability
supernova - finally seems to have been confirmed by observations.
Norbert Langer
doi:10.1038/462579a
http://www.nature.com/nature/journal/v462/n7273/full/462579a.html
Neuroscience: Unbearable lightness of touch pp580-581
Following inflammation or nerve injury, stimuli that are normally
perceived as innocuous can evoke persistent pain. A population of
neurons that contributes to this syndrome has now been identified.
Liam J. Drew and Amy B. MacDermott
doi:10.1038/462580a
http://www.nature.com/nature/journal/v462/n7273/full/462580a.html
Structural biology: Steps in the right direction pp581-583
The ring-shaped helicase enzyme Rho moves along RNA using ATP as an
energy source. Coordinating ATP hydrolysis with nucleic-acid binding
seems to determine the direction and mechanism of helicase movement.
Smita S. Patel
doi:10.1038/462581a
http://www.nature.com/nature/journal/v462/n7273/full/462581a.html
Atomic physics: Neutral atoms put in charge pp584-585
An elegant experiment shows that atoms subjected to a pair of laser
beams can behave like electrons in a magnetic field, as demonstrated
by the appearance of quantized vortices in a neutral superfluid.
Martin Zwierlein
doi:10.1038/462584a
http://www.nature.com/nature/journal/v462/n7273/full/462584a.html
Cell biology: Stairway to the proteasome pp585-586
The study of fast and intricate enzyme reactions requires methods that
have the speed and sophistication to match. Such an approach reveals
the way in which proteins are tagged with ubiquitin for destruction.
Malavika Raman and J. Wade Harper
doi:10.1038/462585a
http://www.nature.com/nature/journal/v462/n7273/full/462585a.html
----------------------
REVIEW
----------------------
Forcing cells to change lineages pp587-594
Thomas Graf and Tariq Enver
doi:10.1038/nature08533
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08533.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08533.html
----------------------
ARTICLES
----------------------
Direct cell reprogramming is a stochastic process amenable to acceleration
pp595-601
Overexpression of certain transcription factors can reprogram somatic cells
into induced pluripotent stem (iPS) cells; however, only a minority of donor
somatic cells can be reprogrammed to pluripotency. Here, this reprogramming
is shown to be a continuous stochastic process where almost all mouse donor
cells eventually give rise to iPS cells on continued growth and
transcription
factor expression; changing certain parameters results in accelerated iPS
cell formation.
Jacob Hanna et al.
doi:10.1038/nature08592
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08592.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08592.html
A gate-latch-lock mechanism for hormone signalling by abscisic acid
receptors
pp602-608
The plant hormone abscisic acid (ABA) is a regulator of plant growth,
development and responses to environmental stresses. Recently, the
PYR/PYL/RCAR family of START proteins was found to bind ABA and mediate
inactivation of downstream effectors. The crystal structures of apo and
ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex is now r
eported and analysed, revealing a gate-latch-lock mechanism underlying ABA
signalling.
Karsten Melcher et al.
doi:10.1038/nature08613
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08613.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08613.html
Structural basis of abscisic acid signalling pp609-614
The plant hormone abscisic acid (ABA) is a regulator of plant growth,
development and responses to environmental stresses. Within plants, the
PYR/PYL/RCAR family of START proteins receives ABA to inhibit the
phosphatase
activity of the group-A protein phophatases 2C (PP2Cs). Here, the crystal
structures of ABA bound to its receptor PYL1 and a complex formed between
ABA, PYL1 and the PP2C protein ABI1 are presented, shedding light on the
structural basis of ABA signalling.
Ken-ichi Miyazono et al.
doi:10.1038/nature08583
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08583.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08583.html
Detection of sequential polyubiquitylation on a millisecond timescale
pp615-619
Conjugation of ubiquitin chains onto proteins is an important
post-translational
modification that regulates the stability, localization and activity of
substrate proteins. A series of enzymes known as E1, E2 and E3 mediate
assembly of ubiquitin chains but the pathway remains unclear. Theoretical
and experimental methodologies are now introduced to study the formation
of ubiquitin chains at millisecond time resolution, demonstrating that
substrate polyubiquitylation proceeds sequentially.
Nathan W. Pierce, Gary Kleiger, Shu-ou Shan and Raymond J. Deshaies
doi:10.1038/nature08595
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08595.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08595.html
----------------------
LETTERS
----------------------
Extreme particle acceleration in the microquasar
Cygnus[thinsp]X-3 pp620-623
Super-massive black holes in active galaxies can accelerate particles to
relativistic energies, producing jets with associated [gamma]-ray emission.
Galactic 'microquasars' also produce relativistic jets; however, apart from
an isolated event detected in Cygnus X-1, there has hitherto been no
systematic
evidence for the acceleration of particles to gigaelectronvolt or higher
energies in a microquasar. Here, a report of four [gamma]-ray flares with
energies above 100 MeV from the microquasar Cygnus X-3 illuminates this
important problem.
M. Tavani et al.
doi:10.1038/nature08578
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08578.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08578.html
Supernova 2007bi as a pair-instability explosion pp624-627
Extremely massive stars with initial masses of more than 140 solar masses
end their lives when pressure-supporting photons turn into electron-positron
pairs, leading to a violent contraction that triggers a nuclear explosion,
unbinding the star in a pair-instability supernova. Here, the mass of the
exploding core of supernova SN 2007bi is estimated at around 100 solar
masses,
in which case theory unambiguously predicts a pair-instability supernova.
Further observations are well fitted by models of pair-instability
supernovae.
A. Gal-Yam et al.
doi:10.1038/nature08579
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08579.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08579.html
Synthetic magnetic fields for ultracold neutral atoms pp628-632
Atomic Bose-Einstein condensates can be used to study many-body phenomena
that occur in more complex material systems; however, the charge neutrality
of these systems prevents intriguing phenomena that occur for charged
particles
in a magnetic field. Rotation can be used to create a synthetic magnetic
field,
but such fields are of limited strength. An optically synthesized magnetic
field for ultracold neutral atoms that is not subject to the limitations of
rotating systems is now experimentally realized.
Y.-J. Lin et al.
doi:10.1038/nature08609
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08609.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08609.html
Controlling photonic structures using optical forces pp633-636
Optical forces can be used to manipulate small objects; for instance, in
optical tweezers. However, it is challenging to manipulate the optical
response of photonic structures using optical forces because of the large
forces that are required to induce appreciable changes in the geometry of
the structure. Here, a resonant structure made of silicon nitride is
demonstrated whose optical response can be efficiently statically controlled
using relatively weak attractive and repulsive optical forces.
Gustavo S. Wiederhecker, Long Chen, Alexander Gondarenko and Michal Lipson
doi:10.1038/nature08584
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08584.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08584.html
Half-precessional dynamics of monsoon rainfall near the East African Equator
pp637-641
Extensive records exist with which to assess the relationship between
external
climate forcings - such as changes in insolation - and climate variability
for
middle and high latitudes, but records from equatorial regions are
relatively
few, especially from regions experiencing the passage of the Intertropical
Convergence Zone. A continuous and well-resolved climate-proxy record of
hydrological variability during the past 25,000 years from equatorial East
Africa is now presented and analysed.
Dirk Verschuren et al.
doi:10.1038/nature08520
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08520.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08520.html
Common dependence on stress for the two fundamental laws of statistical
seismology pp642-645
The Gutenberg-Richter relation and the Omori-Utsu law, both power laws, are
two of the long-standing relationships of statistical seismology. Here,
aftershock sequences are described according to the faulting style of their
main shocks, showing that the time delay before the onset of the power-law
aftershock decay rate is on average shorter for thrust main shocks than for
normal fault earthquakes. These similar dependences on the faulting style
indicate that both the fundamental power laws are governed by the state of
stress.
Clement Narteau, Svetlana Byrdina, Peter Shebalin and Danijel Schorlemmer
doi:10.1038/nature08553
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08553.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08553.html
Regulation of adaptive behaviour during fasting by hypothalamic Foxa2
pp646-650
The lateral hypothalamic area is the 'feeding centre' in the brain. During
fasting, the neuropeptides orexin and melanin-concentrating hormone (MCH)
are
released in this area and stimulate food intake. The expression of orexin
and
MCH is now shown to be regulated by the transcription factor Foxa2, a
downstream target of insulin signalling. The results show that Foxa2 can
act as a metabolic sensor to integrate metabolic signals, adaptive behaviour
and physiological responses.
Jose P. Silva et al.
doi:10.1038/nature08589
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08589.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08589.html
Injury-induced mechanical hypersensitivity requires C-low threshold
mechanoreceptors pp651-655
Despite the contribution of mechanical pain to the morbidity associated with
inflammation and trauma, the primary sensory neurons that convey this
sensation have not been identified. Using knockout mice, the loss of the
low abundance vesicular glutamate transporter VGLUT3, expressed by a small
subset of peripheral sensory neurons projecting to areas implicated in
persistent pain caused by injury, is now shown to specifically impair
mechanical pain sensation.
Rebecca P. Seal et al.
doi:10.1038/nature08505
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08505.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08505.html
Exceptional structured noncoding RNAs revealed by bacterial metagenome
analysis pp656-659
Existing DNA sequence databases carry only a tiny fraction of the total
amount of DNA sequence space from bacterial species. Bioinformatics searches
of genomic DNA from bacteria commonly identify new noncoding RNAs (ncRNAs)
such as riboswitches. Here, an updated computational pipeline is used to
discover ncRNAs that rival the known large ribozymes in size and structural
complexity; other such RNAs probably remain to be discovered.
Zasha Weinberg, Jonathan Perreault, Michelle M. Meyer and Ronald R. Breaker
doi:10.1038/nature08586
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08586.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08586.html
In vitro reconstitution of an abscisic acid signalling pathway pp660-664
The plant hormone abscisic acid (ABA) is a regulator of plant growth,
development and responses to environmental stresses. Although several
proteins have been reported to function as ABA receptors and many more
are known to be involved in ABA signalling, the identities of ABA receptors
remain controversial and the mechanism of signalling unclear. ABA-mediated
signalling is now reconstituted in vitro, defining a minimal set of core
components of the pathway.
Hiroaki Fujii et al.
doi:10.1038/nature08599
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08599.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08599.html
The abscisic acid receptor PYR1 in complex with abscisic acid pp665-668
The plant hormone abscisic acid (ABA) has, among other things, a central
role in coordinating the adaptive response in situations of decreased water
availability. A family of intracellular ABA receptors, named PYR/PYL/RCAR,
has recently been identified. Here, the crystal structure of Arabidopsis
thaliana PYR1, which consists of a dimer in which one of the subunits is
bound to ABA, is presented.
Julia Santiago et al.
doi:10.1038/nature08591
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08591.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08591.html
Hidden alternative structures of proline isomerase essential for catalysis
pp669-673
X-ray crystallography and NMR spectroscopy are two powerful tools to
determine
the three-dimensional structures and characterize the dynamic properties of
proteins. The two methods are now combined to structurally unravel
interconverting
substrates of a human proline isomerase. Crystallographic approaches are
used
to define minor protein conformations and, combined with NMR analysis, to
show
how collective motions contribute to the catalytic power of an enzyme.
James S. Fraser et al.
doi:10.1038/nature08615
Abstract:
http://www.nature.com/nature/journal/v462/n7273/abs/nature08615.html
Article:
http://www.nature.com/nature/journal/v462/n7273/full/nature08615.html
----------------------
ERRATA
----------------------
Remote triggering of fault-strength changes on the San Andreas fault at
Parkfield
p674
Taka'aki Taira, Paul G. Silver, Fenglin Niu and Robert M. Nadeau
doi:10.1038/nature08545
http://www.nature.com/nature/journal/v462/n7273/full/nature08545.html
El Nino in a changing climate p674
Sang-Wook Yeh et al.
doi:10.1038/nature08546
http://www.nature.com/nature/journal/v462/n7273/full/nature08546.html
Integration of neuronal clones in the radial cortical columns by EphA and
ephrin-A signalling p674
Masaaki Torii, Kazue Hashimoto-Torii, Pat Levitt and Pasko Rakic
doi:10.1038/nature08547
http://www.nature.com/nature/journal/v462/n7273/full/nature08547.html
----------------------
TECHNOLOGY FEATURES
----------------------
Microscopy: Ever-increasing resolution pp675-678
Overcoming the limitations of spatial and temporal resolution to image
within a cell is no easy feat. Kelly Rae Chi examines the latest
diffraction-busting technologies.
Kelly Rae Chi
doi:10.1038/462675a
http://www.nature.com/nature/journal/v462/n7273/full/462675a.html
Microscopy: Breaking the light barrier p676
doi:10.1038/462676a
http://www.nature.com/nature/journal/v462/n7273/full/462676a.html
Microscopy: Table of suppliers pp679-680
doi:10.1038/462679a
http://www.nature.com/nature/journal/v462/n7273/full/462679a.html
----------------------
FUTURES
----------------------
Press '1' to begin p688
The art of conversation.
Nye Joell Hardy
doi:10.1038/462688a
http://www.nature.com/nature/journal/v462/n7273/full/462688a.html
| 《Nature》目录要览 — 2011-04-28出版 |
| 《Nature》目录要览：2011-01-20出版 |
| 《Nature》目录要览：2010-12-23出版 |
| 《Nature》目录要览：2010-12-16出版 |
| 《Nature》目录要览：2010-12-09出版 |
| 《Nature》目录要览：2010-12-02出版 |
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