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2008年10月16日Nature中文摘要
封面故事:新合成蛋白的易位路径
Structure of a complex of the ATPase SecA and the protein-translocation
channel
新合成的蛋白通过一个在演化中保留下来的蛋白传导通道或易位子(在真核细胞中被称
为Sec61;在原核细胞中被称为SecY)穿过真核内质网膜或原核胞质膜被移位。在细菌
中,SecA ATPase被认为是SecY通道的“发动机”。Tom Rapoport及其同事所发表的两
篇论文报告了人们等待已久的来自细菌的SecA-SecY复合物的结构。本期封面所示的该
结构,显示了这一复合物中两部分之间的主要构形变化,说明SecA利用一个双螺旋“手
指”将易位蛋白推入SecY的胞质漏斗(cytoplasmic funnel)中。交联研究为这一机制
提供了进一步的实验支持。在第三篇论文中,Osamu Nureki及其同事介绍了与一个反
-SecY Fab片段结合在一起的SecY的晶体结构,显示了该通道的一个开启前状态。这三
篇论文一起为了解一个易位蛋白所选择的路径提供了新线索。在News and Views文章
中,Anastassios Economou分析了这项研究工作对人们目前关于这一“令人吃惊的细胞
纳米机器”的认识有何影响。(Article p. 936; Letters pp. 984, 988; News &
Views)


脊椎动物从鳍状形式向肢状形式的过渡(Fins to limbs: joining the dots)
The cranial endoskeleton of Tiktaalik roseae
脊椎动物向陆地过渡中所涉及的形态变化(包括它们出现的次序)的细节非常少见。化
石记录太粗略,不能给出每个特征的时间线,但通过分析泥盆纪化石Tiktaalik roseae
(鱼类和四足动物之间的一种过渡形式)脑壳的多个标本,Downs等人填补了这些空白
中的其中一些。虽然从很多方面来讲都是原始的,但T. roseae的一些特征接近四足动
物状态。而且,参照关于Tiktaalik形态的这一新观点,从鳍状化石形式向肢状化石形
式的过渡就比较容易理解了。(Article p. 925)


神经母细胞瘤易患基因ALK中发现多种突变(ALK in neuroblastoma)
Identification of ALK as a major familial neuroblastoma predisposition gene
神经母细胞瘤是最常见的小儿癌症。这种疾病有一个强烈的家族联系,而且30年以前科
学家就曾预测,这种疾病有一个遗传元素。现在,四个研究小组报告,他们在神经母细
胞瘤患者的酪氨酸受体ALK((anaplastic lymphoma kinase)中发现了多种突变。ALK
充当神经母细胞瘤的一种易患基因,而且体细胞点突变是在零星的神经母细胞瘤病例中
出现的。这些突变有助于提高ALK的激酶活性,在体内可改变细胞和显示致瘤活性。ALK
抑制药物可抑制神经母细胞瘤细胞的增殖,所以有可能用作抗癌药物。(Article p.
930; Letters pp. 967, 971, 975; News & Views)


深层宇宙中的低频射电晕(Distant haloes in prospect)
A low-frequency radio halo associated with a cluster of galaxies
下一代射电天文望远镜将进入几乎完全未知的领域,以前所未有的分辨率和灵敏度在低
射电频率对宇宙进行观测。一组新的低频星团的发现,让我们有机会一瞥这种望远镜所
可能发现的奥秘。用“巨型米波射电天文望远镜”(位于印度普内以北附近)所做深度
观测,显示了一个与合并星团Abell 521相关的低频射电晕。这个晕有一个极陡的射电
谱,使得它难以被在1.4 GHz(其他所有已知的射电晕都是在这个频率被研究的)进行
的观测工作探测到。这个射电谱支持一种湍动加速机制,后者预测,宇宙中很多射电晕
都应当主要在低频发射。(Letter p. 944)


高温超导体中金属相的性质(High-temperature superconductors show they’re
metal)
Quantum oscillations in an overdoped high-Tc superconductor
除了具有较高超导过渡温度(Tcs)外,铜氧化物超导体还具有多种新颖的物理性质,
受这些性质启发,科学家提出很多理论来解释它们的电子基态。一个值得关注的话题是
这些化合物中金属相的性质,尤其是,相干电子状态或准粒子是怎样通过掺杂(添加痕
量杂质)从反铁磁性绝缘体出现的。Vignolle等人报告了对在过度掺杂的超导体
Tl2Ba2CuO6+δ中量子振荡(即电和磁响应作为磁场的一个函数所发生的振荡)的观
测。这些振荡表明,存在一个由占Brillouin区三分之二的、定义明确的准粒子构成的
很大的费米表面。测定结果证实,可以将超导罩过度掺杂的一边描述为一种具有普遍性
的费米液体(Fermi-liquid),而且也说明,超导性中所涉及的重要载荷子实质上与在
正常金属中所发现的载荷子是相似的。(Letter p. 952)


克服自组装有机电子器件缺陷的方法(Inorganic electronics: the only way is
up)
Bottom-up organic integrated circuits
在有机电子学中,人们的一个长久愿望是,利用某些类型分子的自组织性质来组装关键
器件结构,而不用人为干预,这就是微电子学中“由下向上”(bottom up)的方法。
这种分子的单个自组装层已经以SAMFETs(自组装单层场效应晶体管)形式成功实现,
但这样做成的器件的性能一直让人失望,主要是由于单层中存在缺陷以及层内电子耦合
较差。现在Smits等人发现,这些局限性可通过以化学方法设计组分分子、以确保分子
紧密地、高度有序地堆积来克服。这样做成的SAMFETs具有良好的电学性能和很高的可
重现性,他们通过将超过300个这种晶体管组合成一个功能性集成电路演示了这一点。
(Letter p. 956; Author page; www.nature.com/podcast


太古代异常热地幔的存在得到证实(The Archean mantle: some like it hot)
Oxidation state of iron in komatiitic melt inclusions indicates hot Archaean
mantle
科马提岩(一种火山岩,由地幔岩石异乎寻常地高度熔化形成,主要发生在太古代)的
起源是一个很有争议的话题。它们被认为是由异常热的地幔的无水熔化产生的,或是由
在只比今天稍高一点儿的温度下有水熔化产生的。现在,Berry等人已经确定了来自津
巴布韦Belingwe的一种距今27亿年以前的科马提岩岩浆的原始样品中铁的氧化状态。他
们的发现与一种原料岩石近乎无水熔化的假设是已知的,这种原料岩石所具有的氧化状
态与今天海床玄武岩的氧化状态相似。这些结果表明,Belingwe熔融物是大约为
1,700?C的高地幔温度造成的,而不是在有水条件下熔化的,从而证实了太古代异常热
地幔的存在。(Letter p. 960; News & Views)


一对“医生鱼”之间合作方式的理论和实验研究(Evolution of cooperation: two
heads are better than one)
Pairs of cooperating cleaner fish provide better service quality than
singletons
不相关个体之间合作的演化对于社会科学和自然科学领域的研究人员来说都是一个谜。
更深了解这一现象的一个可能的障碍是,理论工作者和实验工作者有各行其是的倾向。
Bshary等人通过将博弈理论模拟方法、野外观测和实验验证在一项关于合作现象的一个
迄今尚未有人探索过的问题的研究中结合起来,从而避免了理论与实验的脱离,而他们
所研究的这个问题是名为“半拟隆头鱼”的“医生鱼”(或称“清洁鱼”)与它们的客
户鱼的稳定雌雄对之间的清洁互助关系。理论预测,两个服务提供者应当比单个服务提
供者向其客户提供更高质量的服务,只要它们相互合作就行。野外观测和实验都证实了
该模型预测。一对“医生鱼”成功的关键是这样一个事实:当一个清洁者从其客户身上
吃掉皮外寄生虫时,另一个可继续进行其所喜欢的欺骗行为,即吃其客户的粘液,与此
同时仍可保证客户满意。(Letter p. 964; Author page)


Rem1的接合对细胞周期的影响(Cell cycle: what a difference a splice makes)
Promoter-driven splicing regulation in fission yeast
酵母基因组分析表明,从有丝分裂向形成配子的减数分裂的转化与基因表达谱所发生的
一个骤变有关。只在减数分裂过程中表达的一种蛋白是细胞周期蛋白Rem1,该蛋白增强
减数分裂前的基因内重组,保证减数分裂的顺利进行。现在,Moldon等人发现,Rem1在
裂殖酵母Saccharomyces pombe中的表达不仅在转录层面上受控,而且也被接合控制。
在有丝分裂细胞中,Fkh2转录因子与Rem1启动子的结合会产生一个能留住其内含子
(introns)的转录,从而只会有一个短蛋白产生,该蛋白影响重组水平。在减数分裂
细胞中,一个减数分裂特定的转录因子Mei4与Rem1启动子的结合会导致Rem1的接合,并
产生活性细胞周期蛋白。所以,两个转录因子可对同一基因的接合进行不同的修饰。
(Letter p. 997; News & Views)


----------------------
NEWS AND VIEWS
----------------------
Structural biology: Clamour for a kiss pp879-880
Precisely how proteins snake their way through channels in cell membranes is
unclear. Complexes between the SecY channel and its motor protein, and the
use of a 'molecular endoscope', provide fascinating clues.
Anastassios Economou
doi:10.1038/455879a
http://www.nature.com/nature/journal/v455/n7215/full/455879a.html

Condensed-matter physics: Surviving the transition pp880-881
Observations of the birth of a superfluid have uncovered details of the
microphysics of phase transitions. Whether these results can be used to
model such transitions in the early Universe is an open question.
Kristian Helmerson
doi:10.1038/455880a
http://www.nature.com/nature/journal/v455/n7215/full/455880a.html

Earth science: Deducing a reducing mantle pp881-883
Increasingly sophisticated techniques are being used to persuade ancient
rocks to yield information about conditions on and in the early Earth
[mdash] for instance, about the oxidation state of the mantle.
William F. McDonough
doi:10.1038/455881a
http://www.nature.com/nature/journal/v455/n7215/full/455881a.html

Cancer: A ringleader identified pp883-884
The childhood cancer neuroblastoma can either run in families or occur
sporadically. Several studies find that the gene ALK is a chief offender in
this disease, because its germline mutations mediate both forms.
Charis Eng
doi:10.1038/455883a
http://www.nature.com/nature/journal/v455/n7215/full/455883a.html

Philosophy of science: Theories of almost everything pp884-885
A provocative contribution to the logic of science extends the theorems of
Kurt Godel and Alan Turing, and bears on thinking about prediction, the
standard model of particles, and quantum gravity.
P.-M. Binder
doi:10.1038/455884a
http://www.nature.com/nature/journal/v455/n7215/full/455884a.html

Molecular biology: Bound to splice pp885-886
Messenger RNAs don't usually correspond exactly to DNA [mdash] portions of
the primary transcript, known as introns, are removed by splicing. A study
reveals new ways in which splicing can be regulated.
Bruce Futcher and Janet K. Leatherwood
doi:10.1038/455885a
http://www.nature.com/nature/journal/v455/n7215/full/455885a.html

50 & 100 years ago p886
doi:10.1038/455886a
http://www.nature.com/nature/journal/v455/n7215/full/455886a.html

Nano-optics: Optical antennas tuned to pitch p887
Mapping out the resonant modes of optical antennas is part of a largely
unexplored terrain [mdash] but not any more, as a study that applies a
luminescence technique to gold antennas demonstrates.
Lukas Novotny
doi:10.1038/455887a
http://www.nature.com/nature/journal/v455/n7215/full/455887a.html

Oceanography: Ripples run deep p888
Tiny, wind-generated ripples on the sea surface can interact and produce
pressure changes felt on the ocean floor. The same line of study points to a
basic distinction between two types of surface wave.
Steve Elgar
doi:10.1038/455888a
http://www.nature.com/nature/journal/v455/n7215/full/455888a.html

----------------------
INSIGHT
----------------------
EDITORIAL
Neuropsychiatric disease p889
I-han Chou and Tanguy Chouard
doi:10.1038/455889a
http://www.nature.com/nature/journal/v455/n7215/full/455889a.html

INTRODUCTION
A glimmer of light for neuropsychiatric disorders pp890-893
Steven E. Hyman
doi:10.1038/nature07454
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07454.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07454.html

REVIEW ARTICLE
The molecular neurobiology of depression pp894-902
Vaishnav Krishnan and Eric J. Nestler
doi:10.1038/nature07455
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07455.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07455.html

Neuroligins and neurexins link synaptic function to cognitive
disease pp903-911
Thomas C. Sudhof
doi:10.1038/nature07456
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07456.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07456.html

Failure of neuronal homeostasis results in common neuropsychiatric
phenotypes pp912-918
Melissa B. Ramocki and Huda Y. Zoghbi
doi:10.1038/nature07457
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07457.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07457.html

Copy-number variations associated with neuropsychiatric
conditions pp919-923
Edwin H. Cook Jr and Stephen W. Scherer
doi:10.1038/nature07458
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07458.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07458.html

----------------------
Advance Online Publication
----------------------
The cranial endoskeleton of Tiktaalik roseae pp925-929
The Devonian fossil Tiktaalik roseae represents a transitional form between
fishes and tetrapods. This paper presents a detailed examination of the
braincase of this creature. Although primitive in many respects, some
features nod to the tetrapod state.
Jason P. Downs, Edward B. Daeschler, Farish A. Jenkins and Neil H. Shubin
doi:10.1038/nature07189
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07189.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07189.html

Identification of ALK as a major familial neuroblastoma predisposition
gene pp930-935
ALK is identified as a neuroblastoma predisposition gene. Germline mutations
were found in ALK, a tryrosine kinase receptor, in affected families. In
addition, somatic point mutations in ALK were found in sporadic cases of
neuroblastomas. ALK mutations seem to lead to constitutive activation of its
kinase activity and promote cell proliferation.
Yael P. Mosse et al.
doi:10.1038/nature07261
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07261.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07261.html

Structure of a complex of the ATPase SecA and the protein-translocation
channel pp936-943
This study reports the structure of the SecA-SecY complex from bacteria. The
structure reveals major conformational changes between both partners and
provides novel insights into the path taken by a translocating protein.
Jochen Zimmer, Yunsun Nam and Tom A. Rapoport
doi:10.1038/nature07335
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07335.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07335.html

A low-frequency radio halo associated with a cluster of
galaxies pp944-947
Clusters of galaxies are the largest gravitationally bound objects in the
Universe. Magnetic fields and relativistic particles are mixed with the gas
as revealed by giant 'radio haloes'. A radio halo at low frequencies
associated with the merging cluster Abell 521 is reported. This halo has an
extremely steep radio spectrum that makes it difficult to detect with
observations at 1.4 GHz. The spectrum supports a turbulent acceleration
mechanism, which predicts that many radio haloes in the Universe should emit
mainly at low frequencies.
G. Brunetti et al.
doi:10.1038/nature07379
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07379.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07379.html

Spontaneous vortices in the formation of Bose-Einstein
condensates pp948-951
This paper presents an experimental and theoretical study of the
Bose-Einstein condensation phase transition of a trapped atomic gas. The
vortices formed spontaneously during condensation are observed and
characterized, and the results provide further understanding of the
development of coherence in superfluids.
Chad N. Weiler et al.
doi:10.1038/nature07334
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07334.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07334.html

Quantum oscillations in an overdoped high-Tc superconductor pp952-955
This paper reports the observation of quantum oscillations in the overdoped
superconductor Tl2Ba2CuO6+[delta] that show the existence of a large Fermi
surface of well-defined quasiparticles covering two-thirds of the Brillouin
zone. These measurements firmly establish the applicability of a generalized
Fermi-liquid picture on the overdoped side of the superconducting dome.
B. Vignolle et al.
doi:10.1038/nature07323
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07323.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07323.html

Bottom-up organic integrated circuits pp956-959
An ambition in the field of organic electronics has been to harness the
self-organizing properties of certain classes of molecules to assemble key
device structures without human intervention. Single, self-assembled layers
of such molecules have been successfully implemented in transistors, but the
devices' properties have not been promising, largely due to defects in the
monolayers and poor electronic coupling between the molecules within the
layers. It is now shown how such limitations can be overcome, by carefully
tuning the properties of the molecules through chemical design to ensure
dense, highly ordered packing in the self-assembled monolayer. The good
electrical performance and high reproducibility of the resulting devices is
demonstrated by combining over 300 of them into a functional integrted
circuit.
Edsger C. P. Smits et al.
doi:10.1038/nature07320
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07320.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07320.html

Oxidation state of iron in komatiitic melt inclusions indicates hot Archaean
mantle pp960-963
The original iron isotope ratios of a 2.7 billion-year-old komatiitic magma
from Belingwe, Zimbabwe have been determined. These measurements are
consistent with near-anhydrous melting of a source with similar oxidation
state to that of present-day ocean-floor basalt. The results support the
identification of the Belingwe komatiite as a product of high mantle
temperatures of [sim] 1,700 [deg]C, rather than melting under hydrous
conditions, confirming the existence of anomalously hot mantle in the
Archean.
Andrew J. Berry et al.
doi:10.1038/nature07377
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07377.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07377.html

Pairs of cooperating cleaner fish provide better service quality than
singletons pp964-966
The evolution of cooperation between unrelated individuals is a puzzle that
attracts interest both in the social and in the natural sciences.
Theoretical concepts may fail to capture essential features of real life
cooperation. This paper focuses on the cleaning mutualism between cleaner
wrasse and their client fish. A game theoretical model predicts that two
providers should offer a higher service quality to clients than single
providers, as long as they cooperate among each other. Field observations
and an experimental test confirm the model prediction.
Redouan Bshary, Alexandra S. Grutter, Astrid S. T. Willener and Olof Leimar
doi:10.1038/nature07184
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07184.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07184.html

Somatic and germline activating mutations of the ALK kinase receptor in
neuroblastoma pp967-970
This is one of four papers in this issue that identifies mutations in the
tyrosine kinase receptor ALK in neuroblastoma, the most frequent childhood
cancer. ALK is found to be a neuroblastoma predisposition gene and somatic
points mutations were found in sporadic cases of neuroblastoma. These
mutations lead the ALK kinase activation and are able to transform cells and
display tumourigenic activity in vivo. ALK inhibitors decrease neuroblastoma
cell proliferating and are potential anti-cancer drugs for the treatment of
neuroblastoma.
Isabelle Janoueix-Lerosey et al.
doi:10.1038/nature07398
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07398.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07398.html

Oncogenic mutations of ALK kinase in neuroblastoma pp971-974
This is one of four papers in this issue that identifies mutations in the
tyrosine kinase receptor ALK in neuroblastoma, the most frequent childhood
cancer. ALK is found to be a neuroblastoma predisposition gene and somatic
points mutations were found in sporadic cases of neuroblastoma. These
mutations lead the ALK kinase activation and are able to transform cells and
display tumourigenic activity in vivo. ALK inhibitors decrease neuroblastoma
cell proliferating and are potential anti-cancer drugs for the treatment of
neuroblastoma.
Yuyan Chen et al.
doi:10.1038/nature07399
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07399.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07399.html

Activating mutations in ALK provide a therapeutic target in
neuroblastoma pp975-978
This is one of four papers in this issue that identifies mutations in the
tyrosine kinase receptor ALK in neuroblastoma, the most frequent childhood
cancer. ALK is found to be a neuroblastoma predisposition gene and somatic
points mutations were found in sporadic cases of neuroblastoma. These
mutations lead the ALK kinase activation and are able to transform cells and
display tumourigenic activity in vivo. ALK inhibitors decrease neuroblastoma
cell proliferating and are potential anti-cancer drugs for the treatment of
neuroblastoma.
Rani E. George et al.
doi:10.1038/nature07397
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07397.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07397.html

Conformational transition of Sec machinery inferred from bacterial SecYE
structures pp988-991
A crystal structure of SecY bound to an anti SecY Fab fragment revealing a
pre-open state of the channel is presented.
Tomoya Tsukazaki et al.
doi:10.1038/nature07421
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07421.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07421.html

Promoter-driven splicing regulation in fission yeast pp997-1000
Rem1 expression is controlled not only at the level of transcription, but
also by splicing. In mitotic cells, binding of the Fkh2 transcription factor
to the rem1 promoter yields a transcript that retains its introns so that
only a short protein is produced; this protein affects recombination levels.
In meiotic cells, the binding of the meiosis-specific trancription factor
Mei4 to the rem1 promoter results in splicing of rem1, yielding the cyclin
isoform. Thus, this work demonstrates that two transcription factors can
differentially affecting splicing of the same gene.
Alberto Moldon et al.
doi:10.1038/nature07325
Abstract:
http://www.nature.com/nature/journal/v455/n7215/abs/nature07325.html?lang=en
Article:
http://www.nature.com/nature/journal/v455/n7215/full/nature07325.html
 
    
 


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