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2007年8月16日Nature中文摘要
 BIOX.CN  来源：生命经纬    2007年08月16日
封面故事：根据结构来预测未知酶功能的新方法
Structure-based activity prediction for an enzyme of unknown function
如果一种新发现的蛋白与已知的酶相似时，经常有可能来推断其功能，否则，结
构-功能关系是非常难以判断的。现在，Johannes Hermann等人利用一种变通的
分子对接方法（一种用来寻找潜在药物的计算机辅助的模拟方法），设计出一种
根据结构来预测某种具有未知活性的酶的功能的方法。试验用的酶是Tm0936，来
自极端喜热的Thermotoga maritima。对接实验预测，它将使
5-methylthioadenosine和S-adenosylhomocysteine去胺化；这一点已在化学
上、并从与一个反应产物相结合的该蛋白的X-射线晶体结构得到了证实。这种酶
没有与已知的腺苷胺化酶相似的明显序列，甚至它所参与的通道似乎也是新颖
的。如果这一新方法也适用于其他酶，那么它应当成为一种有力工具，来确定关
键的酶在体内是如何发挥作用的。（Article p. 775; News & Views）


癌症与衰老之间的关系（Cancer and ageing）
The common biology of cancer and ageing
癌细胞的恒久生命与导致人死亡的衰老过程看起来似乎是相对立的。但令人吃惊
的是，癌细胞和衰老过程的生物学基础却是相合的。基因组不稳定、端粒功能和
自噬作用等在关于癌症和衰老的论文中都能见到。研究人员已经在肿瘤发生与细
胞衰老之间发现了联系。线粒体代谢对这两个现象来说都是中心内容。Finkel等
人从历史角度向我们介绍了癌症和衰老的共同生物学基础：从第一次意识到人类
癌细胞—HeLa细胞—在培养中有可能继续分裂一直谈到系统生物学方法的问世。
（Review Article p. 767）


Mira的历史轨迹（Mira image）
A turbulent wake as a tracer of 30,000 years of Mira's mass loss
history
Mira是一组处在恒星演化后期阶段、质量低于或稍微高于太阳质量的恒星中的一
个。这些恒星通过它们发出的风对其主星系中的恒星和行星形成产生直接影响。
Martin等人报告，他们发现了一个发射紫外线的弓激波（bow shock）和其涡动
的尾迹，在天空中延伸超过2度。这个弓激波源自Mira很大的空间速度及其风与
星际介质之间的相互作用。这种风的尾迹是过去3万年的Mira低质量历史所留下
的一个痕迹。（Letter p. 780）


薛定谔猫及其应用（Schr?dinger’s fat cats）
Generation of optical 'Schr?dinger cats' from photon number states
薛定谔猫思想实验说明这样一个思想：量子物理允许原子保持在超级位置状态。
这种猫被想象处于一个盒子中，里面还有一个放射性原子，该原子被设计用来在
其衰变时释放一种毒素。在“经典”世界中，猫要么是死的，要么是活的；但在
由关闭的“盒子”构成的量子世界中，猫可以同时是死的和活的。自由传播的光
的一个“猫”状态被定义为由完全分开的准经典状态构成的一个量子超级位置；
这种状态对于量子信息处理及在验证量子理论的实验中可能有用。最近的实验成
功地生成了可见光薛定谔“小猫”—太小而无法实用。现在，研究人员将理论和
实验结合起来，来制定一个协议，按照这个协议，能够产生挤压的薛定谔猫状
态，大到足以能够进行实际应用。（Letter p. 784）


第一种单原子金属玻璃（Testing one’s metal）
Vitrification of a monatomic metallic liquid
玻璃有很多形式。对于金属玻璃来说，通常需要多种成分来避免在正常液体冷却
过程中发生结晶。（一个引人注目的例外是由两种成分组成的金属玻璃
Zr50Cu50）。现在，Bhat等人利用关于控制玻璃形成的因素的最近的理论发现来
确定金属液体锗成功玻璃化的实验条件。 他们不仅生成了第一种单原子金属玻
璃，而且还发现了这一体系中罕见的液体-液体相变的证据。（Letter p. 787;
News & Views）


近地表臭氧对植被的影响（Ozone’s double life）
Indirect radiative forcing of climate change through ozone effects on
the land-carbon sink
植物和土壤目前正在通过储存大约四分之一由人类排放的二氧化碳来减缓全球变
暖，但这种减缓效应可能会因为近地表臭氧的进一步增加而被葬送。与高空中的
臭氧（阻挡有害的紫外线）不同的是，低空臭氧损害植物，降低它们吸收二氧化
碳的能力，加快全球变暖。当前的气候模型一般包括低空臭氧（一种弱温室气
体）的地球变暖效应，但并不直接考虑其对植被的影响。 一项新的研究表明，
人们所预测的由于工业排放所造成的臭氧浓度增加，将显著降低植物生产力。这
种间接效应很可能比臭氧作为一种温室气体的直接效应对全球变暖的贡献更大。
（Letter p. 791）


云母可能是造成圣*安德烈斯断层高速蠕动的原因（Talc about friction）
Talc-bearing serpentinite and the creeping section of the San Andreas
fault
沿圣*安德烈斯断层某些区段的高速蠕动，曾被认为是由与蛇纹化岩石相关的较
低的断层强度造成的。这种观点是有问题的，因为蛇纹矿的摩擦强度被认为太
大，无法满足断层强度的限制条件。现在，Diane Moore 和Michael Rymer报
告，云母（软的硅酸镁矿物质，我们比较熟悉其纯净形式，即滑石粉）可能是该
断层高蠕动速度背后的原因。他们在“圣*安德烈斯断层深度观测项目”
（SAFOD）主洞2005年钻探期间所收集的蛇纹岩样品中发现了云母。云母在高温
下的摩擦力低到足以满足断层上剪切力的限制条件，而且其固有的稳定滑动行为
与断层的蠕动也是一致的。（Letter p. 795; News & Views）


雄性出走是为了适应雌性（The seeds of dispersal）
Female mate-choice drives the evolution of male-biased dispersal in a
social mammal
群居哺乳动物的迁徙是一个重要事件，因为它对繁殖成功有很大影响。通常都是
雄性进行迁徙，但在坦桑尼亚Ngorongoro Crater保护区对斑点猎豹群落所做的
新的研究工作表明，雄性仅仅是按照雌性的安排行事。雄性的迁徙决定是对简单
的雌性交配选择规则的一种适应性反应，这些规则的形成，很可能是为了避免近
亲繁殖。（Letter p. 798）


Lkb1突变与肺癌发病（Lkb1 and cancer causation）
LKB1 modulates lung cancer differentiation and metastasis
Lkb1肿瘤抑制基因所发生的突变见于Peutz–Jeghers综合症患者，这些患者癌症
发病率增加。现在，Lkb1突变已在非小细胞肺癌的鳞状肿瘤亚型中被发现。在一
个Lkb1缺失与K-Ras突变相结合的肺癌小鼠模型中，出现了比只有K-Ras突变时更
有侵略性的肿瘤，这些肿瘤经常被划分为鳞状大细胞肿瘤。所以，Lkb1缺失调控
肺癌分化，而Lkb1缺失还可能是预测疾病发展和扩散的一个有用的标记。由LKB1
调控的通道代表可能的治疗目标。（Letter p. 807）


产生Andrimid的生物合成通道被确定（A new line in antibiotics）
A transglutaminase homologue as a condensation catalyst in antibiotic
assembly lines
Andrimid是一种相对较“新”的抗生素，从几种不同类型的细菌中分离出来，通
过阻断细菌脂肪酸生物合成中的第一步来发挥作用。主要是由于这种新颖的作用
方式，它对于能够抵抗多种药物的病原体具有活性。现在，产生Andrimid的生物
合成通道已经被确定，从而为获取具有治疗潜力的新的一类Andrimid衍生物提供
了一条途径。对迄今已经测序的微生物基因组所进行的数据挖掘工作，发现了转
谷氨酰胺酶类的酶AdmF的同源物，这种酶是Andrimid生物合成通道的关键成分，
埋在很多孤立生物合成基因簇内，其天然产物尚未被识别出来。看来，这种类型
的化合物是普遍存在的，更多“新”抗生素在等待我们去发现。（Letter p.
824）


----------------------
NEWS AND VIEWS
----------------------
Biological chemistry: Enzymes line up for assembly pp755 - 756
Many enzymes have a series of catalytic sites, lined up like beads on
a string. A previously unknown link in one of these molecular assembly
lines involves an unexpected approach to a common biochemical
reaction.
Nicholas M. Llewellyn and Jonathan B. Spencer
doi:10.1038/448755a
http://www.nature.com/nature/journal/v448/n7155/full/448755a.html

Seismology: Talc at fault pp756 - 757
The behaviour of the San Andreas fault varies along its length ― it
slips in some places and creeps in others. The discovery of the
ultrasoft mineral talc in rocks from deep inside the fault could help
to explain why.
Christopher Wibberley
doi:10.1038/448756a
http://www.nature.com/nature/journal/v448/n7155/full/448756a.html

Biochemistry: Designer enzymes pp757 - 758
Evolution has crafted thousands of enzymes that are efficient
catalysts for a plethora of reactions. Human attempts at enzyme design
trail far behind, but may benefit from exploiting evolutionary
tactics.
Michael P. Robertson and William G. Scott
doi:10.1038/448757a
http://www.nature.com/nature/journal/v448/n7155/full/448757a.html

Materials science: Metal turned to glass pp758 - 759
In order to form a glass by cooling a liquid, the normal process of
solid crystallization must be bypassed. Achieving that for a pure
metal had seemed impossible ― until pressure was applied to liquid
germanium.
Gilles Tarjus
doi:10.1038/448758a
http://www.nature.com/nature/journal/v448/n7155/full/448758a.html

Parkinson's disease: Pro-survival effects of PINK1 pp759 - 760
However parkinsonism is initiated, the progressive symptoms are
similarly devastating. So insights from analyses of gene mutations
linked to these disorders should aid a better general understanding of
them.
Asa Abeliovich
doi:10.1038/448759a
http://www.nature.com/nature/journal/v448/n7155/full/448759a.html

Astrophysics: Photons from a hotter hell pp760 - 762
Blazars are massive black holes sending out particle jets at close to
the speed of light. Stupendously fast, intense bursts of highly
energetic γ-rays indicate that the blazar environment is even more
extreme than was thought.
Trevor Weekes
doi:10.1038/448760a
http://www.nature.com/nature/journal/v448/n7155/full/448760a.html

50 & 100 Years Ago p761
doi:10.1038/448761a
http://www.nature.com/nature/journal/v448/n7155/full/448761a.html

Computational biochemistry: Models of transition pp762 - 763
Is it possible to determine the role of an enzyme from its structure?
The latest findings suggest that it is, and prove the point by
predicting the substrate for an enzyme of unknown function.
JoAnne Stubbe
doi:10.1038/448762a
http://www.nature.com/nature/journal/v448/n7155/full/448762a.html

Earth science: Coastal catastrophe in Phoenicia p763
Tim Lincoln
doi:10.1038/448763a
http://www.nature.com/nature/journal/v448/n7155/full/448763a.html

Correction p763
doi:10.1038/448763b
http://www.nature.com/nature/journal/v448/n7155/full/448763b.html

Obituary: Anne McLaren (1927-2007) pp764 - 765
Inspiring reproductive biologist and mammalian geneticist.
Azim Surani and Jim Smith
doi:10.1038/448764a
http://www.nature.com/nature/journal/v448/n7155/full/448764a.html

Obituary: Donald Michie (1923-2007) p765
Father of artificial intelligence in Britain.
Margaret Boden
doi:10.1038/448765a
http://www.nature.com/nature/journal/v448/n7155/full/448765a.html

----------------------
REVIEWS
----------------------
The common biology of cancer and ageing pp767 - 774
Toren Finkel, Manuel Serrano and Maria A. Blasco
doi:10.1038/nature05985
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature05985.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature05985.html

----------------------
ARTICLES
----------------------
Structure-based activity prediction for an enzyme of unknown
function pp775 - 779
A computational approach is used to predict the function of an
uncharacterized enzyme by docking high-energy intermediate forms of
candidate metabolites into its purported binding site. The docking
experiments predicted that the enzyme would be able to deaminate
intermediates of 5-methylthioadenosine and S-adenosylhomocysteine, a
prediction confirmed by biochemical experiments and examination of the
X-ray crystal structure of the protein.
Johannes C. Hermann et al.
doi:10.1038/nature05981
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature05981.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature05981.html

----------------------
LETTERS
----------------------
A turbulent wake as a tracer of 30,000[thinsp]years of Mira's mass
loss history pp780 - 783
Mira is one of a class of low-to-intermediate mass stars in the late
stages of stellar evolution. This paper reports the discovery of an
ultraviolet-emitting bow shock and turbulent wake extending over 2
degrees on the sky, arising from Mira's large space velocity and the
interaction between its wind and the interstellar medium. This wind
wake is a tracer of the last 30,000 years of Mira's mass-loss history.
D. Christopher Martin et al.
doi:10.1038/nature06003
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06003.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06003.html

Generation of optical /`Schrodinger cats/' from photon number
states pp784 - 786
This paper theoretically and experimentally demonstrates a protocol
that allows the generation of arbitrarily large squeezed Schrodinger
cat states, using homodyne detection and photon number states as
resources. The protocol was implemented with light pulses containing
two photons, producing a squeezed Schrodinger cat state with a
negative Wigner function.
Alexei Ourjoumtsev, Hyunseok Jeong, Rosa Tualle-Brouri and Philippe
Grangier
doi:10.1038/nature06054
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06054.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06054.html

Vitrification of a monatomic metallic liquid pp787 - 790
Recent theoretical insights into the factors controlling glass
formation have been used to determine the experimental conditions for
successful vitrification of metallic liquid germanium. Not only has
the first monatomic metallic glass been created, but evidence for a
rare liquid-liquid phase transition in this system has also been
found.
M. H. Bhat et al.
doi:10.1038/nature06044
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06044.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06044.html

Indirect radiative forcing of climate change through ozone effects on
the land-carbon sink pp791 - 794
The impact of projected changes in ozone levels on the land-carbon
sink are estimated with the help of a global carbon cycle model, which
accounts for interactions between ozone and carbon dioxide through
stomatal closure. A significant suppression of the global land carbon
sink as increases in ozone concentrations affect plant productivity is
found. The resulting indirect radiative forcing by ozone effects on
plants could contribute more to global warming than the direct
radiative forcing.
S. Sitch, P. M. Cox, W. J. Collins and C. Huntingford
doi:10.1038/nature06059
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06059.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06059.html

Talc-bearing serpentinite and the creeping section of the San Andreas
fault pp795 - 797
This paper reports the discovery of talc in cuttings of serpentinite
collected during drilling of the San Andreas Fault Observatory at
Depth main hole in 2005. The frictional strength of talc at elevated
temperatures is sufficiently low to meet the constraints on shear
strength of the fault, and its inherently stable sliding behaviour is
consistent with fault creep. Talc may therefore provide the connection
between serpentinite and creep in the San Andreas fault.
Diane E. Moore and Michael J. Rymer
doi:10.1038/nature06064
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06064.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06064.html

Female mate-choice drives the evolution of male-biased dispersal in a
social mammal pp798 - 801
Dispersal affects lifetime reproductive success, and in group-living
mammals it is usually the males that disperse. Male-biased dispersal
in the spotted hyaena (Crocuta crocuta) is the result of an adaptive
response of males to female mate choice associated with inbreeding
avoidance.
O. P. Honer et al.
doi:10.1038/nature06040
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06040.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06040.html

Correlation between neural spike trains increases with firing
rate pp802 - 806
Deciphering a 'neural code' usually requires measurement of either the
rate of spike (electrical impulses) production or the spike synchrony.
However, these two measures are not independent, as higher rates are
associated with higher synchrony. It is further shown that the
connection between rate and synchrony enhances information coding.
Jaime de la Rocha et al.
doi:10.1038/nature06028
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06028.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06028.html

LKB1 modulates lung cancer differentiation and metastasis pp807
- 810
Mutations in the Lbk1 tumour suppressor gene are found in the squamous
carcinoma subtype of non-small cell lung cancers for the first time.
In a mouse model for lung cancer in which Lkb1 loss is combined with
Kras mutations, more aggressive tumours arise than with Kras mutations
alone and often these are classified as squamous carcinomas, thus Lkb1
loss modulates lung cancer differentiation.
Hongbin Ji et al.
doi:10.1038/nature06030
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06030.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06030.html

Cdk1 is sufficient to drive the mammalian cell cycle pp811 - 815
Mouse lacking all interphase Cdks (Cdk2, Cdk3, Cdk4 and Cdk6) undergo
organogenesis and develop to midgestation, and individual cells
lacking all 3 kinases are able to proliferate. However, Cdk1 is shown
to be absolutely essential for cell division during the first stages
of embryonic development.
David Santamaria et al.
doi:10.1038/nature06046
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06046.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06046.html

Small self-RNA generated by RNase L amplifies antiviral innate
immunity pp816 - 819
RNA molecules in virus-infected cells trigger interferon production
and initiate antiviral innate immunity. This paper shows that small
RNA cleavage products from 'self' RNA, generated by the antiviral
endonuclease RNas L, can initiate and amplify antiviral responses.
Krishnamurthy Malathi, Beihua Dong, Michael Gale, Jr and Robert H.
Silverman
doi:10.1038/nature06042
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06042.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06042.html

Break-induced replication and telomerase-independent telomere
maintenance require Pol32 pp820 - 823
Break-induced replication repair (BIR) of a DNA double-strand break
requires Polα and Polδ to initiate replication, while Polε is
needed to extend the replication patch. This BIR also uniquely
requires Pol32, a Polδ subunit that is not necessary for normal
replication.
John R. Lydeard, Suvi Jain, Miyuki Yamaguchi and James E. Haber
doi:10.1038/nature06047
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06047.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06047.html

A transglutaminase homologue as a condensation catalyst in antibiotic
assembly lines pp824 - 827
AdmF catalyzes the formation of the first amide bond in andrimid
biosynthesis, indicating that AdmF is a novel biosynthetic enzyme that
acts as a stand-alone amide synthase between protein-bound,
thiotemplated substrates in an antibiotic enzymatic assembly line.
This constitutes the first report of a transglutaminase-like enzyme
recruited for the assembly of an antibiotic.
Pascal D. Fortin, Christopher T. Walsh and Nathan A. Magarvey
doi:10.1038/nature06068
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06068.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06068.html

Selection and evolution of enzymes from a partially randomized
non-catalytic scaffold pp828 - 831
New enzymatic activities can be evolved de novo (that is, without the
need for prior mechanistic information) by using mRNA-display.
Functional proteins were selected for from an in vitro translated
protein library of high complexity and it was possible to isolate
novel RNA ligases that exhibited rate enhancements of more than two
million-fold.
Burckhard Seelig and Jack W. Szostak
doi:10.1038/nature06032
Abstract:
http://www.nature.com/nature/journal/v448/n7155/abs/nature06032.html
Article:
http://www.nature.com/nature/journal/v448/n7155/full/nature06032.html
 
    
 


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