View source for 5nik


==Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump==
<SX load='5nik' size='340' side='right' viewer='molstar' caption='[[5nik]], [[Resolution|resolution]] 3.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5nik]] is a 11 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5NIK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5NIK 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]] 3.3&#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=5nik FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5nik OCA], [https://pdbe.org/5nik PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5nik RCSB], [https://www.ebi.ac.uk/pdbsum/5nik PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5nik ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TOLC_ECOLI TOLC_ECOLI] Outer membrane channel, which is required for the function of several efflux systems such as AcrAB-TolC, AcrEF-TolC, EmrAB-TolC and MacAB-TolC. These systems are involved in export of antibiotics and other toxic compounds from the cell. TolC is also involved in import of colicin E1 into the cells.<ref>PMID:6337123</ref> <ref>PMID:11274125</ref> <ref>PMID:15228545</ref> <ref>PMID:18955484</ref> <ref>PMID:23176499</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism.

Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump.,Fitzpatrick AWP, Llabres S, Neuberger A, Blaza JN, Bai XC, Okada U, Murakami S, van Veen HW, Zachariae U, Scheres SHW, Luisi BF, Du D Nat Microbiol. 2017 May 15;2:17070. doi: 10.1038/nmicrobiol.2017.70. PMID:28504659<ref>PMID:28504659</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5nik" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</SX>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Bai X-C]]
[[Category: Blaza JN]]
[[Category: Du D]]
[[Category: Fitzpatrick AWP]]
[[Category: Llabres S]]
[[Category: Luisi BF]]
[[Category: Murakami S]]
[[Category: Neuberger A]]
[[Category: Okada U]]
[[Category: Scheres SHW]]
[[Category: Zachariae U]]
[[Category: Van Veen HW]]