View source for 4uaq


==Crystal structure of the accessory translocation ATPase, SecA2, from Mycobacterium tuberculosis==
<StructureSection load='4uaq' size='340' side='right'caption='[[4uaq]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4uaq]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Mycobacterium_tuberculosis_H37Rv Mycobacterium tuberculosis H37Rv]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4UAQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4UAQ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></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=4uaq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4uaq OCA], [https://pdbe.org/4uaq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4uaq RCSB], [https://www.ebi.ac.uk/pdbsum/4uaq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4uaq ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SECA2_MYCTU SECA2_MYCTU] Part of the Sec protein translocase complex. Interacts with the SecYEG preprotein conducting channel. Has a central role in coupling the hydrolysis of ATP to the transfer of proteins into and across the cell membrane, serving as an ATP-driven molecular motor driving the stepwise translocation of polypeptide chains across the membrane.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
While SecA (1) is the ATPase component of the major bacterial secretory (Sec) system, mycobacteria and some Gram-positive pathogens have a second paralog, SecA2. In bacteria with two SecA paralogs, each SecA is functionally distinct and they cannot compensate for one another. Compared to SecA1, SecA2 exports a distinct and smaller set of substrates, some of which have roles in virulence. In the mycobacterial system, some SecA2-dependent substrates lack a signal peptide while others contain a signal peptide but possess features in the mature protein that necessitate a role for SecA2 in their export. It is unclear how SecA2 functions in protein export, and one open question is whether SecA2 works with the canonical SecYEG channel to export proteins. In this study, we report the structure of M. tuberculosis SecA2, which is the first structure of any SecA2 protein. A high level of structural similarity is observed between SecA2 and SecA1. The major structural difference is the absence of the helical wing domain, which is likely to play a role in how M. tuberculosis SecA2 recognizes its unique substrates. Importantly, structural features critical to the interaction between SecA1 and SecYEG are preserved in SecA2. Further, suppressor mutations of a dominant-negative secA2 mutant map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG or the translocating polypeptide substrate. These results support a model in which the mycobacterial SecA2 works with SecYEG. IMPORTANCE: SecA2 is a paralog of SecA1, which is the ATPase of the canonical bacterial Sec secretion system. SecA2 has a non-redundant function with SecA1, and SecA2 exports a distinct and smaller set of substrates than SecA1. This work reports the crystal structure of SecA2 of Mycobacterium tuberculosis (the first SecA2 structure reported for any organism). Many of the structural features of SecA1 are conserved in the SecA2 structure, including putative contacts with the SecYEG channel. Several structural differences are also identified that could relate to the unique function and selectivity of SecA2. Suppressor mutations of a secA2 mutant map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG.

Structural similarities and differences between two functionally distinct SecA proteins: the Mycobacterium tuberculosis SecA1 and SecA2.,Swanson S, Ioerger TR, Rigel NW, Miller BK, Braunstein M, Sacchettini JC J Bacteriol. 2015 Dec 14. pii: JB.00696-15. PMID:26668263<ref>PMID:26668263</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4uaq" style="background-color:#fffaf0;"></div>

==See Also==
*[[SecA|SecA]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mycobacterium tuberculosis H37Rv]]
[[Category: Braunstein M]]
[[Category: Ioerger TR]]
[[Category: Miller BK]]
[[Category: Rigel NW]]
[[Category: Sacchettini JC]]
[[Category: Swanson-Smith S]]