@article {65277, title = {Structure of the vesicular stomatitis virus L protein in complex with Its phosphoprotein cofactor.}, journal = {Cell Reports}, volume = {30}, year = {2020}, month = {2020 Jan 07}, pages = {53-60.e5}, abstract = {

The large (L) proteins of non-segmented, negative-strand RNA viruses are multifunctional enzymes that produce capped, methylated, and polyadenylated mRNA and replicate the viral genome. A phosphoprotein (P), required for efficient RNA-dependent RNA polymerization from the viral ribonucleoprotein (RNP) template, regulates the function and conformation of the L protein. We report the structure of vesicular stomatitis virus L in complex with its P cofactor determined by electron cryomicroscopy at 3.0\ {\r A} resolution, enabling us to visualize bound segments of P. The contacts of three P segments with multiple L domains show how P induces a closed, compact, initiation-competent conformation. Binding of P to L positions its N-terminal domain adjacent to a putative RNA exit channel for efficient encapsidation of newly synthesized genomes with the nucleoprotein and orients its C-terminal domain to interact with an RNP template. The model shows that a conserved tryptophan in the priming loop can support the initiating 5{\textquoteright} nucleotide.

}, issn = {2211-1247}, doi = {10.1016/j.celrep.2019.12.024}, author = {Jenni, Simon and Bloyet, Louis-Marie and Diaz-Avalos, Ruben and Liang, Bo and Whelan, Sean P J and Grigorieff, Nikolaus and Harrison, Stephen C} } @article {48302, title = {Conformational states of a soluble, uncleaved HIV-1 envelope trimer.}, journal = {Journal of Virology}, volume = {91}, year = {2017}, month = {2017 Mar 01}, pages = {e00175-17}, abstract = {

HIV-1 envelope spike [Env; trimeric (gp160)3, cleaved to (gp120/gp41)3] induces membrane fusion, leading to viral entry. It is also the viral component targeted by neutralizing antibodies. Vaccine development requires production, in quantities suitable for clinical studies, of a recombinant form that resembles functional Env. HIV-1 gp140 trimers - the uncleaved ectodomains of (gp160)3 - from a few selected viral isolates adopt a compact conformation with many antigenic properties of native Env spikes. One is currently being evaluated in a clinical trial. We report here low-resolution (20{\r A}) cryoEM (electron cryomicroscopy) structures of this gp140 trimer, which adopts two principal conformations, one closed and the other slightly open. The former is indistinguishable at this resolution from those adopted by a stabilized, cleaved trimer (SOSIP) or by a membrane-bound Env trimer with truncated cytoplasmic tail (EnvΔCT). The latter conformation is closer to a partially open Env trimer than to the fully open conformation induced by CD4. These results show that a stable, uncleaved HIV-1 gp140 trimer has a compact structure close to that of native Env.IMPORTANCE Development of any HIV vaccine with a protein component (either prime or boost) requires production of a recombinant form to mimic the trimeric, functional HIV-1 envelope spike, in quantities suitable for clinical studies. Our understanding of the envelope structure has depended in part on a cleaved, soluble trimer, known as SOSIP.664, stabilized by several modifications including an engineered disulfide. This construct, difficult to produce in large quantities, has yet to induce better antibody responses than other envelope-based immunogens, even in animal models. The uncleaved ectodomain of the envelope protein, called gp140, has also been made as a soluble form to mimic the native Env present on the virion surface. Most HIV-1 gp140 preparations are not stable, however, and of inhomogeneous conformation. The results presented here show that gp140 preparations from suitable isolates can adopt a compact, native-like structure, supporting its use as a vaccine candidate.

}, issn = {1098-5514}, doi = {10.1128/JVI.00175-17}, author = {Liu, Yuhang and Pan, Junhua and Cai, Yongfei and Grigorieff, Nikolaus and Harrison, Stephen C and Chen, Bing} } @article {48489, title = {CryoEM structure of an influenza virus receptor-binding site antibody-antigen interface.}, journal = {Journal of Molecular Biology}, volume = {429}, year = {2017}, month = {2017 May 12}, pages = {1829-39}, abstract = {

Structure-based vaccine design depends on extensive structural analyses of antigen-antibody complexes. Single-particle electron cryomicroscopy (cryoEM) can circumvent some of the problems of x-ray crystallography as a pipeline for obtaining the required structures. We have examined the potential of single-particle cryoEM for determining the structure of influenza-virus hemagglutinin (HA):single-chain Fv (scFv) complexes, by studying a complex we failed to crystallize in pursuing an extended project of the human immune response to influenza vaccines. The result shows that a combination of cryoEM and molecular modeling can yield details of the antigen:antibody interface, although small variation in the twist of the rod-like HA trimer limited the overall resolution to about 4.5{\r A}. Comparison of principal 3D classes suggests ways to modify the HA trimer to overcome this limitation. A closely related antibody from the same donor did yield crystals when bound with the same HA, giving us an independent validation of the cryoEM results The two structures also augment our understanding of receptor-binding site recognition by antibodies that neutralize a wide range of influenza-virus variants.

}, issn = {1089-8638}, doi = {10.1016/j.jmb.2017.05.011}, author = {Liu, Yuhang and Pan, Junhua and Jenni, Simon and Raymond, Donald D and Caradonna, Tim and Do, Khoi T and Schmidt, Aaron G and Harrison, Stephen C and Grigorieff, Nikolaus} } @article {47353, title = {Data publication with the structural biology data grid supports live analysis.}, journal = {Nature Communications}, volume = {7}, year = {2016}, month = {2016 Mar 07}, pages = {10882}, abstract = {

Access to experimental X-ray diffraction image data is fundamental for validation and reproduction of macromolecular models and indispensable for development of structural biology processing methods. Here, we established a diffraction data publication and dissemination system, Structural Biology Data Grid (SBDG; data.sbgrid.org), to preserve primary experimental data sets that support scientific publications. Data sets are accessible to researchers through a community driven data grid, which facilitates global data access. Our analysis of a pilot collection of crystallographic data sets demonstrates that the information archived by SBDG is sufficient to reprocess data to statistics that meet or exceed the quality of the original published structures. SBDG has extended its services to the entire community and is used to develop support for other types of biomedical data sets. It is anticipated that access to the experimental data sets will enhance the paradigm shift in the community towards a much more dynamic body of continuously improving data analysis.

}, issn = {2041-1723}, doi = {10.1038/ncomms10882}, author = {Meyer, Peter A and Socias, Stephanie and Key, Jason and Ransey, Elizabeth and Tjon, Emily C and Buschiazzo, Alejandro and Lei, Ming and Botka, Chris and Withrow, James and Neau, David and Rajashankar, Kanagalaghatta and Anderson, Karen S and Baxter, Richard H and Blacklow, Stephen C and Boggon, Titus J and Bonvin, Alexandre M J J and Borek, Dominika and Brett, Tom J and Caflisch, Amedeo and Chang, Chung-I and Chazin, Walter J and Corbett, Kevin D and Cosgrove, Michael S and Crosson, Sean and Dhe-Paganon, Sirano and Di Cera, Enrico and Drennan, Catherine L and Eck, Michael J and Eichman, Brandt F and Fan, Qing R and Ferr{\'e}-D{\textquoteright}Amar{\'e}, Adrian R and Christopher Fromme, J and Garcia, K Christopher and Gaudet, Rachelle and Gong, Peng and Harrison, Stephen C and Heldwein, Ekaterina E and Jia, Zongchao and Keenan, Robert J and Kruse, Andrew C and Kvansakul, Marc and McLellan, Jason S and Modis, Yorgo and Nam, Yunsun and Otwinowski, Zbyszek and Pai, Emil F and Pereira, Pedro Jos{\'e} Barbosa and Petosa, Carlo and Raman, C S and Rapoport, Tom A and Roll-Mecak, Antonina and Rosen, Michael K and Rudenko, Gabby and Schlessinger, Joseph and Schwartz, Thomas U and Shamoo, Yousif and Sondermann, Holger and Tao, Yizhi J and Tolia, Niraj H and Tsodikov, Oleg V and Westover, Kenneth D and Wu, Hao and Foster, Ian and Fraser, James S and Maia, Filipe R N C and Gonen, Tamir and Kirchhausen, Tom and Diederichs, Kay and Crosas, Merc{\`e} and Sliz, Piotr} } @article {48316, title = {Structure of the L protein of vesicular stomatitis virus from electron cryomicroscopy.}, journal = {Cell}, volume = {162}, year = {2015}, month = {2015 Jul 16}, pages = {314-27}, abstract = {

The large (L) proteins of non-segmented, negative-strand RNA viruses, a group that includes Ebola and rabies viruses, catalyze RNA-dependent RNA polymerization with viral ribonucleoprotein as template, a non-canonical sequence of capping and methylation reactions, and polyadenylation of viral messages. We have determined by electron cryomicroscopy the structure of the vesicular stomatitis virus (VSV) L protein. The density map, at a resolution of 3.8 {\r A}, has led to an atomic model for nearly all of the 2109-residue polypeptide chain, which comprises three enzymatic domains (RNA-dependent RNA polymerase [RdRp], polyribonucleotidyl transferase [PRNTase], and methyltransferase) and two structural domains. The RdRp resembles the corresponding enzymatic regions of dsRNA virus polymerases and influenza virus polymerase. A loop from the PRNTase (capping) domain projects into the catalytic site of the RdRp, where it appears to have the role of a priming loop and to couple product elongation to large-scale conformational changes in L.

}, keywords = {Cryoelectron Microscopy, DNA-Directed RNA Polymerases, Models, Molecular, Protein Structure, Tertiary, Sequence Homology, Amino Acid, Transcription, Genetic, Vesicular stomatitis Indiana virus, Viral Proteins}, issn = {1097-4172}, doi = {10.1016/j.cell.2015.06.018}, author = {Liang, Bo and Li, Zongli and Jenni, Simon and Rahmeh, Amal A and Morin, Benjamin M and Grant, Timothy and Grigorieff, Nikolaus and Harrison, Stephen C and Whelan, Sean P J} } @article {6324, title = {Location of the dsRNA-dependent polymerase, VP1, in rotavirus particles.}, journal = {Journal of Molecular Biology}, volume = {425}, year = {2013}, month = {2013 Jan 9}, pages = {124-32}, abstract = {

Double-stranded RNA (dsRNA) viruses transcribe and replicate RNA within an assembled, inner capsid particle; only plus-sense mRNA emerges into the intracellular milieu. During infectious entry of a rotavirus particle, the outer layer of its three-layer structure dissociates, delivering the inner double-layered particle (DLP) into the cytosol. DLP structures determined by X-ray crystallography and electron cryomicroscopy (cryoEM) show that the RNA coils uniformly into the particle interior, avoiding a "fivefold hub" of more structured density projecting inward from the VP2 shell of the DLP along each of the twelve 5-fold axes. Analysis of the X-ray crystallographic electron density map suggested that principal contributors to the hub are the N-terminal arms of VP2, but reexamination of the cryoEM map has shown that many features come from a molecule of VP1, randomly occupying five equivalent and partly overlapping positions. We confirm here that the electron density in the X-ray map leads to the same conclusion, and we describe the functional implications of the orientation and position of the polymerase. The exit channel for the nascent transcript directs the nascent transcript toward an opening along the 5-fold axis. The template strand enters from within the particle, and the dsRNA product of the initial replication step exits in a direction tangential to the inner surface of the VP2 shell, allowing it to coil optimally within the DLP. The polymerases of reoviruses appear to have similar positions and functional orientations.

}, keywords = {Capsid, Computer-Assisted, Cryoelectron Microscopy, Crystallography, Double-Stranded, Image Processing, Messenger, Models, Molecular, RNA, Rotavirus, Viral, Viral Core Proteins, Virus Assembly, X-Ray}, issn = {1089-8638}, doi = {10.1016/j.jmb.2012.10.011}, author = {Estrozi, Leandro F and Settembre, Ethan C and Goret, Ga{\"e}l and McClain, Brian and Zhang, Xing and Chen, James Z and Grigorieff, Nikolaus and Harrison, Stephen C} } @article {6320, title = {Beam-induced motion of vitrified specimen on holey carbon film.}, journal = {Journal of Structural Biology}, volume = {177}, year = {2012}, month = {2012 Mar}, pages = {630-7}, abstract = {

The contrast observed in images of frozen-hydrated biological specimens prepared for electron cryo-microscopy falls significantly short of theoretical predictions. In addition to limits imposed by the current instrumentation, it is widely acknowledged that motion of the specimen during its exposure to the electron beam leads to significant blurring in the recorded images. We have studied the amount and direction of motion of virus particles suspended in thin vitrified ice layers across holes in perforated carbon films using exposure series. Our data show that the particle motion is correlated within patches of 0.3-0.5 μm, indicating that the whole ice layer is moving in a drum-like motion, with accompanying particle rotations of up to a few degrees. Support films with smaller holes, as well as lower electron dose rates tend to reduce beam-induced specimen motion, consistent with a mechanical effect. Finally, analysis of movies showing changes in the specimen during beam exposure show that the specimen moves significantly more at the start of an exposure than towards its end. We show how alignment and averaging of movie frames can be used to restore high-resolution detail in images affected by beam-induced motion.

}, keywords = {Computer-Assisted, Cryoelectron Microscopy, Image Processing}, issn = {1095-8657}, doi = {10.1016/j.jsb.2012.02.003}, author = {Brilot, Axel F and Chen, James Z and Cheng, Anchi and Pan, Junhua and Harrison, Stephen C and Potter, Clinton S and Carragher, Bridget and Henderson, Richard and Grigorieff, Nikolaus} } @article {6319, title = {Movies of ice-embedded particles enhance resolution in electron cryo-microscopy.}, journal = {Structure}, volume = {20}, year = {2012}, month = {2012 Nov 7}, pages = {1823-8}, abstract = {

Low-dose images obtained by electron cryo-microscopy (cryo-EM) are often affected by blurring caused by sample motion during electron beam exposure, degrading signal especially at high resolution. We show here that we can align frames of movies, recorded with a direct electron detector during beam exposure of rotavirus double-layered particles, thereby greatly reducing image blurring caused by beam-induced motion and sample stage instabilities. This procedure increases the efficiency of cryo-EM imaging and enhances the resolution obtained in three-dimensional reconstructions of the particle. Using movies in this way is generally applicable to all cryo-EM samples and should also improve the performance of midrange electron microscopes that may have limited mechanical stability and beam coherence.

}, keywords = {Cryoelectron Microscopy, Ice, Rotavirus}, issn = {1878-4186}, doi = {10.1016/j.str.2012.08.026}, author = {Campbell, Melody G and Cheng, Anchi and Brilot, Axel F and Moeller, Arne and Lyumkis, Dmitry and Veesler, David and Pan, Junhua and Harrison, Stephen C and Potter, Clinton S and Carragher, Bridget and Grigorieff, Nikolaus} } @article {6335, title = {Atomic model of an infectious rotavirus particle.}, journal = {The EMBO Journal}, volume = {30}, year = {2011}, month = {2011 Jan 19}, pages = {408-16}, abstract = {

Non-enveloped viruses of different types have evolved distinct mechanisms for penetrating a cellular membrane during infection. Rotavirus penetration appears to occur by a process resembling enveloped-virus fusion: membrane distortion linked to conformational changes in a viral protein. Evidence for such a mechanism comes from crystallographic analyses of fragments of VP4, the rotavirus-penetration protein, and infectivity analyses of structure-based VP4 mutants. We describe here the structure of an infectious rotavirus particle determined by electron cryomicroscopy (cryoEM) and single-particle analysis at about 4.3 {\r A} resolution. The cryoEM image reconstruction permits a nearly complete trace of the VP4 polypeptide chain, including the positions of most side chains. It shows how the two subfragments of VP4 (VP8(*) and VP5(*)) retain their association after proteolytic cleavage, reveals multiple structural roles for the β-barrel domain of VP5(*), and specifies interactions of VP4 with other capsid proteins. The virion model allows us to integrate structural and functional information into a coherent mechanism for rotavirus entry.

}, keywords = {Capsid Proteins, Cell Membrane, Cryoelectron Microscopy, Crystallography, Models, Molecular, Protein Structure, Rotavirus, Secondary, Virion, Virus Internalization}, issn = {1460-2075}, doi = {10.1038/emboj.2010.322}, author = {Settembre, Ethan C and Chen, James Z and Dormitzer, Philip R and Grigorieff, Nikolaus and Harrison, Stephen C} } @article {6321, title = {Near-atomic resolution reconstructions of icosahedral viruses from electron cryo-microscopy.}, journal = {Current Opinion in Structural Biology}, volume = {21}, year = {2011}, month = {2011 Apr}, pages = {265-73}, abstract = {

Nine different near-atomic resolution structures of icosahedral viruses, determined by electron cryo-microscopy and published between early 2008 and late 2010, fulfil predictions made 15 years ago that single-particle cryo-EM techniques could visualize molecular detail at 3-4A resolution. This review summarizes technical developments, both in instrumentation and in computation, that have led to the new structures, which advance our understanding of virus assembly and cell entry.

}, keywords = {Computer Simulation, Computer-Assisted, Cryoelectron Microscopy, Image Processing, Models, Molecular, Virus Assembly, Viruses}, issn = {1879-033X}, doi = {10.1016/j.sbi.2011.01.008}, author = {Grigorieff, Nikolaus and Harrison, Stephen C} } @article {6340, title = {Structure of clathrin coat with bound Hsc70 and auxilin: mechanism of Hsc70-facilitated disassembly.}, journal = {The EMBO Journal}, volume = {29}, year = {2010}, month = {2010 Feb 3}, pages = {655-65}, abstract = {

The chaperone Hsc70 drives the clathrin assembly-disassembly cycle forward by stimulating dissociation of a clathrin lattice. A J-domain containing co-chaperone, auxilin, associates with a freshly budded clathrin-coated vesicle, or with an in vitro assembled clathrin coat, and recruits Hsc70 to its specific heavy-chain-binding site. We have determined by electron cryomicroscopy (cryoEM), at about 11 A resolution, the structure of a clathrin coat (in the D6-barrel form) with specifically bound Hsc70 and auxilin. The Hsc70 binds a previously analysed site near the C-terminus of the heavy chain, with a stoichiometry of about one per three-fold vertex. Its binding is accompanied by a distortion of the clathrin lattice, detected by a change in the axial ratio of the D6 barrel. We propose that when Hsc70, recruited to a position close to its target by the auxilin J-domain, splits ATP, it clamps firmly onto its heavy-chain site and locks in place a transient fluctuation. Accumulation of the local strain thus imposed at multiple vertices can then lead to disassembly.

}, keywords = {Animals, Auxilins, Biological, Cattle, Clathrin, Clathrin-Coated Vesicles, Cryoelectron Microscopy, HSC70 Heat-Shock Proteins, Models, Molecular, Multiprotein Complexes, Protein Binding, Protein Multimerization, Protein Structure, Quaternary, Secondary}, issn = {1460-2075}, doi = {10.1038/emboj.2009.383}, author = {Xing, Yi and B{\"o}cking, Till and Wolf, Matthias and Grigorieff, Nikolaus and Kirchhausen, Tomas and Harrison, Stephen C} } @article {6336, title = {Subunit interactions in bovine papillomavirus.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {107}, year = {2010}, month = {2010 Apr 6}, pages = {6298-303}, abstract = {

Papillomaviruses, members of a group of dsDNA viruses associated with epithelial growths and tumors, have compact capsids assembled from 72 pentamers of the protein L1. We have determined the structure of bovine papillomavirus by electron cryomicrosopy (cryoEM), at approximately 3.6 A resolution. The density map, obtained from single-particle analysis of approximately 4,000 particle images, shows the trace of the L1 polypeptide chain and reveals how the N- and C-terminal "arms" of a subunit (extensions from its beta-jelly-roll core) associate with a neighboring pentamer. Critical contacts come from the C-terminal arm, which loops out from the core of the subunit, forms contacts (including a disulfide) with two subunits in a neighboring pentamer, and reinserts into the pentamer from which it emanates. This trace corrects one feature of an earlier model. We discuss implications of the structure for virion assembly and for pathways of infectious viral entry. We suggest that it should be possible to obtain image reconstructions of comparable resolution from cryoEM images of asymmetric particles. From the work on papillomavirus described here, we estimate that such a reconstruction will require about 1.5 million images to achieve the same number of averaged asymmetric units; structural variability will increase this number substantially.

}, keywords = {Cryoelectron Microscopy, Models, Molecular, Papillomaviridae, Protein Interaction Domains and Motifs, Protein Structure, Protein Subunits, Quaternary, Tertiary, Viral Envelope Proteins, Virion}, issn = {1091-6490}, doi = {10.1073/pnas.0914604107}, author = {Wolf, Matthias and Garcea, Robert L and Grigorieff, Nikolaus and Harrison, Stephen C} } @article {6342, title = {Molecular interactions in rotavirus assembly and uncoating seen by high-resolution cryo-EM.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {106}, year = {2009}, month = {2009 Jun 30}, pages = {10644-8}, abstract = {

Rotaviruses, major causes of childhood gastroenteritis, are nonenveloped, icosahedral particles with double-strand RNA genomes. By the use of electron cryomicroscopy and single-particle reconstruction, we have visualized a rotavirus particle comprising the inner capsid coated with the trimeric outer-layer protein, VP7, at a resolution (4 A) comparable with that of X-ray crystallography. We have traced the VP7 polypeptide chain, including parts not seen in its X-ray crystal structure. The 3 well-ordered, 30-residue, N-terminal "arms" of each VP7 trimer grip the underlying trimer of VP6, an inner-capsid protein. Structural differences between free and particle-bound VP7 and between free and VP7-coated inner capsids may regulate mRNA transcription and release. The Ca(2+)-stabilized VP7 intratrimer contact region, which presents important neutralizing epitopes, is unaltered upon capsid binding.

}, keywords = {Antigens, Biological, Calcium, Capsid Proteins, Cryoelectron Microscopy, Crystallography, Models, Molecular, Protein Multimerization, Protein Structure, Quaternary, Rotavirus, Viral, Viral Core Proteins, Virion, X-Ray}, issn = {1091-6490}, doi = {10.1073/pnas.0904024106}, author = {Chen, James Z and Settembre, Ethan C and Aoki, Scott T and Zhang, Xing and Bellamy, A Richard and Dormitzer, Philip R and Harrison, Stephen C and Grigorieff, Nikolaus} } @article {45960, title = {Interactions of lipids with aquaporin-0 and other membrane proteins.}, journal = {Pfl{\"u}gers Archiv - European Journal of Physiology}, volume = {456}, year = {2008}, month = {2008 Jul}, pages = {651-61}, abstract = {

The structure of aquaporin-0 (AQP0) has recently been determined by electron crystallography of two-dimensional (2D) crystals and by X-ray crystallography of three-dimensional (3D) crystals. The electron crystallographic structure revealed nine lipids per AQP0 monomer, which form an almost complete bilayer. The lipids adopt a wide variety of conformations and tightly fill the space between adjacent AQP0 tetramers. The conformations of the lipid acyl chains appear to be determined not only by the protein surface but also by the acyl chains of adjacent lipid molecules. In the X-ray structure, the hydrophobic region of the protein is surrounded by a detergent micelle, with two ordered detergent molecules per AQP0 monomer. Despite the different environments, the electron crystallographic and X-ray structures of AQP0 are virtually identical, but they differ in the temperature factors of the atoms that either contact the lipids in the 2D crystals or are exposed to detergents in the 3D crystals. The temperature factors are higher in the X-ray structure, suggesting that the detergent-exposed AQP0 residues are less ordered than the corresponding ones contacting lipids in the 2D crystals. An examination of ordered detergent molecules in crystal structures of other aquaporins and of lipid molecules in 2D and 3D crystals of bacteriorhodopsin suggests that the increased conformational variability of detergent-exposed residues compared to lipid-contacting residues is a general feature.

}, keywords = {Animals, Aquaporins, Crystallization, Eye Proteins, Humans, Lipid Metabolism, Membrane Proteins, Models, Molecular, X-Ray Diffraction}, issn = {0031-6768}, doi = {10.1007/s00424-007-0353-9}, author = {Hite, Richard K and Gonen, Tamir and Harrison, Stephen C and Walz, Thomas} } @article {45957, title = {Lipid-protein interactions in double-layered two-dimensional AQP0 crystals.}, journal = {Nature}, volume = {438}, year = {2005}, month = {2005 Dec 1}, pages = {633-8}, abstract = {

Lens-specific aquaporin-0 (AQP0) functions as a specific water pore and forms the thin junctions between fibre cells. Here we describe a 1.9 A resolution structure of junctional AQP0, determined by electron crystallography of double-layered two-dimensional crystals. Comparison of junctional and non-junctional AQP0 structures shows that junction formation depends on a conformational switch in an extracellular loop, which may result from cleavage of the cytoplasmic amino and carboxy termini. In the centre of the water pathway, the closed pore in junctional AQP0 retains only three water molecules, which are too widely spaced to form hydrogen bonds with each other. Packing interactions between AQP0 tetramers in the crystalline array are mediated by lipid molecules, which assume preferred conformations. We were therefore able to build an atomic model for the lipid bilayer surrounding the AQP0 tetramers, and we describe lipid-protein interactions.

}, keywords = {Animals, Aquaporins, Crystallization, Crystallography, Hydrogen Bonding, Lens, Crystalline, Lipid Bilayers, Membrane Lipids, Models, Molecular, Protein Binding, Protein Structure, Quaternary, Sheep, Water}, issn = {1476-4687}, doi = {10.1038/nature04321}, author = {Gonen, Tamir and Cheng, Yifan and Sliz, Piotr and Hiroaki, Yoko and Fujiyoshi, Yoshinori and Harrison, Stephen C and Walz, Thomas} }