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Volume 465 Issue 7297, 27 May 2010

The structures of the membrane domain of respiratory complex I from Escherichia coli, and of the entire complex I from Thermus thermophilus have been determined. Complex I is the first enzyme of the respiratory chain, and the last component of the respiratory chain for which the mechanism and complete structure were unknown. The structures provide strong clues about coupling mechanism: conformational changes at the interface of the two main domains may drive a long α-helix in a piston-like motion, tilting nearby transmembrane helices and resulting in proton translocation. The cover depicts the T. thermophilus respiratory complex I embedded in a lipid bilayer. Picture credit: Rouslan Efremov/Rikke Schmidt Kjaergaard/Leonid Sazanov.

Postdoc Journal

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Editorial

  • The successful transplantation of a synthesized genome highlights unresolved ethical and security issues posed by synthetic biology.

    Editorial
  • US agencies have moved too slowly in gathering key data on the oil spill in the Gulf of Mexico.

    Editorial
  • Society deserves to see a return on its investment in science, but researchers need help to make their case.

    Editorial
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Research Highlights

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Journal Club

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News

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News Feature

  • Can the science of deception detection help to catch terrorists? Sharon Weinberger takes a close look at the evidence for it.

    • Sharon Weinberger
    News Feature
  • The US National Science Foundation's insistence that every research project addresses 'broader impacts' leaves many researchers baffled. Corie Lok takes a looks at the system.

    • Corie Lok
    News Feature
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Correspondence

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Opinion

  • Plumes of dissolved gas could be used to determine how much oil has leaked into the Gulf of Mexico, says David Valentine — if the studies are done soon.

    • David Valentine
    Opinion
  • Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self-replicating Mycoplasma mycoides.

    Opinion
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Books & Arts

  • A book promoting the use of informatics to help us live greener lives could have been enhanced by following interactive design principles, suggests Nick Salafsky.

    • Nick Salafsky
    Books & Arts
  • Brian Greene, author of best-selling books The Elegant Universe and The Fabric of the Cosmos, is a theoretical physicist at Columbia University, New York. As an orchestral work based on his 2008 children's book, Icarus at the Edge of Time, premieres next week, Greene discusses black holes and how music might portray the physics of warped space-time.

    • Jascha Hoffman
    Books & Arts
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News & Views

  • Fossils from the famed Burgess Shale continue to deliver fresh perspectives on a dramatic episode in evolutionary time. The latest revelations bear on the early history of cephalopod molluscs.

    • Stefan Bengtson
    News & Views
  • The membrane-spanning enzyme known as complex I couples the movement of electrons to that of protons as a way of converting energy. Crystal structures suggest how electron transfer drives proton pumping from afar.

    • Tomoko Ohnishi
    News & Views
  • By swapping the roles of the target and beam in an experiment that is otherwise impossible to implement, researchers have confirmed the doubly magic nature of the neutron-rich radioactive tin isotope 132Sn.

    • Paul Cottle
    News & Views
  • The discovery in Europe of fossils of a small horned dinosaur, a member of a group previously known only from Asia and North America, will prompt a rethink of biogeography at that time in the past.

    • Xing Xu
    News & Views
  • The influence of the region where the lower mantle meets the core extends to Earth's surface. A computational study of mineral properties shows one way forward in understanding this enigmatic zone.

    • James A. Van Orman
    News & Views
  • Paradoxically, the CD95 receptor, a potent inducer of apoptotic cell death, is expressed on most tumour cells. Surprisingly, it turns out to be an important promoter of various cancers.

    • Douglas R. Green
    News & Views
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Article

  • Dynamin is a protein that catalyses the fission of clathrin-coated endocytic vesicles from cellular membranes. To carry out fission, it must hydrolyse GTP. The mechanism by which it does so is unknown, although it does require dynamin's GTPase effector domain (GED). Here, the structure of a minimal GTPase–GED fusion protein constructed from human dynamin 1 is presented. The structure reveals the catalytic machinery and provides new insight into the mechanisms underlying dynamin-catalysed membrane fission.

    • Joshua S. Chappie
    • Sharmistha Acharya
    • Fred Dyda
    Article
  • Complex I is an enzyme of the respiratory chain, and is crucial to cellular energy production: it couples electron transfer between NADH and quinine to proton translocation. Here, structures are presented of the membrane domain of complex I from Escherichia coli, and of the entire complex I from Thermus thermophilus. It is proposed that conformational changes at the interface of the two main domains drive a particular 110-Å-long a-helix in a piston-like motion, tilting nearby transmembrane helices and causing proton translocation.

    • Rouslan G. Efremov
    • Rozbeh Baradaran
    • Leonid A. Sazanov
    Article
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Letter

  • The Chasma Boreale is a large canyon — 500 km long, up to 100 km wide, and nearly 2 km deep — that cuts into the north polar layered deposits on Mars. Quite how it formed has been unclear. However, new penetrating radar imagery has now been used to show that depositional processes, rather than catastrophic events, were responsible.

    • J. W. Holt
    • K. E. Fishbaugh
    • R. J. Phillips
    Letter
  • A pinwheel array of deep troughs has been one of the most perplexing features of the north polar layered deposits on Mars. Many ideas have been put forward about how it formed, but there is as yet no consensus. Here, penetrating radar has been used to rule out erosional cutting as a mechanism for the formation of the array. Instead, it is concluded that the troughs are largely depositional in origin, and have migrated to the poles and upwards in elevation over the past two million years or so.

    • Isaac B. Smith
    • John W. Holt
    Letter
  • Atomic nuclei have a shell structure that allows for 'magic numbers' of neutrons and protons, analogous to the noble gases in atomic physics. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for the fundamental understanding of nuclear structure and nucleosynthesis. Here, a nucleon-transfer technique has been used to measure the single-particle states of 133Sn, revealing the highly magic nature of 132Sn.

    • K. L. Jones
    • A. S. Adekola
    • J. S. Thomas
    Letter
  • The magnetism produced by electrons in a solid can have two components — the spin and orbital moments — that are interchangeable on femtosecond timescales. Here it is shown how rapid changes in these two components can be disentangled, providing insights into the underlying dynamical processes that could be of value for the ultrafast control of information in magnetic recording media.

    • C. Boeglin
    • E. Beaurepaire
    • J.-Y. Bigot
    Letter
  • Here, first-principles methods have been applied to calculate diffusion rates in the mineral post-perovskite under the conditions found in the Earth's lower mantle. The results show that the diffusion of Mg2+ and Si4+ in post-perovskite is extremely anisotropic. This could render post-perovskite up to four orders of magnitude weaker than perovskite, and might reconcile seismic observations of a D” reflector with recent experiments showing that the perovskite to post-perovskite transition is too wide to cause sharp reflectors.

    • M. W. Ammann
    • J. P. Brodholt
    • D. P. Dobson
    Letter
  • Ceratopsians — horned dinosaurs — were distinctive features of the fauna of the Cretaceous period in East Asia and western North America. There have been hints that they might also have occurred elsewhere, but this has not been definitive, until now. The discovery of a ceratopsian, Ajkaceratops kozmai, from what is now Hungary shows that Late Cretaceous biogeography still has surprises in store.

    • Attila Ősi
    • Richard J. Butler
    • David B. Weishampel
    Letter
  • The 505-million-year-old Burgess Shales of British Columbia are justifiably famous for the exquisite preservation of their fossils, and for the extreme oddity of many of them. One such is Nectocaris pteryx, which, from the few fossils available for study, looked like a chordate fused with an arthropod. However, the collection and examination of more fossils of Nectocaris suggests that it in fact represents an early offshoot of cephalopod molluscs — a kind of squid, though with two rather than eight or ten tentacles.

    • Martin R. Smith
    • Jean-Bernard Caron
    Letter
  • Complete genome sequencing has already provided insights into the mutation spectra of several cancer types. Here, the first complete sequences are provided of a primary lung tumour and adjacent normal tissue. Comparison of the two reveals a variety of somatic mutations in the cancer genome, including changes in the KRAS proto-oncogene. The results reveal a distinct pattern of selection against mutations within expressed genes compared to non-expressed genes, and selection against mutations in promoter regions.

    • William Lee
    • Zhaoshi Jiang
    • Zemin Zhang
    Letter
  • Uninterrupted blood flow through the small vessels of the brain is essential for cerebral function and viability. Small clots that form in the vessels can be — but are not always — removed by haemodynamic forces and the fibrinolytic system. Here, a third mechanism for the removal of emboli is described: the endothelial cells that line the vessel walls send out membrane projections that envelop the emboli and move them into the perivascular parenchyma tissue. In aged mice, this process is markedly delayed.

    • Carson K. Lam
    • Taehwan Yoo
    • Jaime Grutzendler
    Letter
  • The protein ephrin-B2 is known to be upregulated during angiogenesis — the growth of new blood vessels — but its precise function has been unclear. Here it is shown that signalling through ephrin-B2 controls vessel sprouting. Mechanistically, ephrin-B2 seems to function in part by regulating the internalization of vascular endothelial growth factor receptors (VEGFRs). The results indicate that blocking ephrin-B2 signalling might be an alternative to blocking VEGFR function to disrupt angiogenesis in tumours.

    • Yingdi Wang
    • Masanori Nakayama
    • Ralf H. Adams
    Letter
  • The protein ephrin-B2 is known to be upregulated during angiogenesis — the growth of new blood vessels — but its precise function has been unclear. Here it is shown that signalling through ephrin-B2 controls vessel sprouting. Mechanistically, ephrin-B2 seems to function in part by regulating the internalization of vascular endothelial growth factor receptors (VEGFRs). The results indicate that blocking ephrin-B2 signalling might be an alternative to blocking VEGFR function to disrupt angiogenesis in tumours.

    • Suphansa Sawamiphak
    • Sascha Seidel
    • Amparo Acker-Palmer
    Letter
  • CD95 is a classical death receptor protein that regulates tissue homeostasis by inducing cell death. Here it is shown, however, that cancer cells depend on CD95 for optimal growth. Without CD95, the incidence of ovarian cancer and liver cancer in mice is reduced, as is the size of any tumours. So CD95 is a double-edged sword, and it may be necessary to reduce, rather than enhance, its activity in order to kill tumour cells.

    • Lina Chen
    • Sun-Mi Park
    • Marcus E. Peter
    Letter
  • The enzyme inositol polyphosphate phosphatase 4A (INPP4A) removes phosphate groups from phosphatidylinositol-3,4-bisphosphate, a key cellular lipid. Here, a crucial role for INPP4A in maintaining the integrity of the brain is described. Mice that lack this enzyme suffer from neurodegeneration in the striatum of the brain, as well as severe involuntary movements. When present, INPP4A protects neurons from a particular type of cell death.

    • Junko Sasaki
    • Satoshi Kofuji
    • Takehiko Sasaki
    Letter
  • Dynamin is a protein that catalyses the scission of clathrin-coated pits at the plasma membrane. The mechanisms of dynamin-catalysed scission remain poorly understood. Here, the structure of the stalk region of human MxA, a dynamin-like protein, is presented. A structural model of MxA oligomerization and stimulated GTP hydrolysis is put forward that has functional implications for all members of the dynamin family.

    • Song Gao
    • Alexander von der Malsburg
    • Oliver Daumke
    Letter
  • Nascent secretory or membrane proteins contain an amino-terminal signal peptide that mediates their targeting to the plasma membrane (in prokaryotes) or endoplasmic reticulum (in eukaryotes). This peptide is recognized by the signal recognition particle (SRP). A universally conserved component of the SRP is known as SRP54 (Ffh in bacteria). Here, the crystal structure of Sulfolobus solfataricus SRP54 fused to a signal peptide is presented, revealing how the signal peptide is recognized by SRP54.

    • Claudia Y. Janda
    • Jade Li
    • Kiyoshi Nagai
    Letter
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Careers Q&A

  • Rafael Jaramillo received the 2010 Rosalind Franklin Young Investigator Award on 4 May from the Advanced Photon Source Users Organization for his work on the fundamentals of magnetism at low temperatures.

    • Virginia Gewin
    Careers Q&A
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Career Brief

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Regions

  • Denmark aims to attract international talent through new initiatives and university reforms. Marta Paterlini outlines the strategy.

    • Marta Paterlini
    Regions
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Futures

  • The sweet smell of the past.

    • Misha Angrist
    Futures
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