View source for 7osl


==Cryo-EM structure of nonameric EPEC SctV-C==
<StructureSection load='7osl' size='340' side='right'caption='[[7osl]], [[Resolution|resolution]] 3.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7OSL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7OSL FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.1&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7osl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7osl OCA], [https://pdbe.org/7osl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7osl RCSB], [https://www.ebi.ac.uk/pdbsum/7osl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7osl ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Type III protein secretion is widespread in Gram-negative pathogens. It comprises the injectisome with a surface-exposed needle and an inner membrane translocase. The translocase contains the SctRSTU export channel enveloped by the export gate subunit SctV that binds chaperone/exported clients and forms a putative ante-chamber. We probed the assembly, function, structure and dynamics of SctV from enteropathogenic E. coli (EPEC). In both EPEC and E. coli lab strains, SctV forms peripheral oligomeric clusters that are detergent-extracted as homo-nonamers. Membrane-embedded SctV9 is necessary and sufficient to act as a receptor for different chaperone/exported protein pairs with distinct C-domain binding sites that are essential for secretion. Negative staining electron microscopy revealed that peptidisc-reconstituted His-SctV9 forms a tripartite particle of approximately 22 nm with a N-terminal domain connected by a short linker to a C-domain ring structure with a approximately 5 nm-wide inner opening. The isolated C-domain ring was resolved with cryo-EM at 3.1 A and structurally compared to other SctV homologues. Its four sub-domains undergo a three-stage "pinching" motion. Hydrogen-deuterium exchange mass spectrometry revealed this to involve dynamic and rigid hinges and a hyper-flexible sub-domain that flips out of the ring periphery and binds chaperones on and between adjacent protomers. These motions are coincident with local conformational changes at the pore surface and ring entry mouth that may also be modulated by the ATPase inner stalk. We propose that the intrinsic dynamics of the SctV protomer are modulated by chaperones and the ATPase and could affect allosterically the other subunits of the nonameric ring during secretion.

Structural Dynamics of the Functional Nonameric Type III Translocase Export Gate.,Yuan B, Portaliou AG, Parakra R, Smit JH, Wald J, Li Y, Srinivasu B, Loos MS, Dhupar HS, Fahrenkamp D, Kalodimos CG, Duong van Hoa F, Cordes T, Karamanou S, Marlovits TC, Economou A J Mol Biol. 2021 Aug 26;433(21):167188. doi: 10.1016/j.jmb.2021.167188. PMID:34454944<ref>PMID:34454944</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7osl" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Fahrenkamp D]]
[[Category: Marlovits TC]]
[[Category: Wald J]]
[[Category: Yuan B]]