View source for 3j9c


==CryoEM single particle reconstruction of anthrax toxin protective antigen pore at 2.9 Angstrom resolution==
<StructureSection load='3j9c' size='340' side='right' caption='[[3j9c]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3j9c]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_cereus_var._anthracis"_(cohn_1872)_smith_et_al._1946 "bacillus cereus var. anthracis" (cohn 1872) smith et al. 1946]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J9C OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3J9C FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">pagA, pag, pXO1-110, BXA0164, GBAA_pXO1_0164 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1392 "Bacillus cereus var. anthracis" (Cohn 1872) Smith et al. 1946])</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3j9c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j9c OCA], [http://pdbe.org/3j9c PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3j9c RCSB], [http://www.ebi.ac.uk/pdbsum/3j9c PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3j9c ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/PAG_BACAN PAG_BACAN]] One of the three proteins composing the anthrax toxin, the agent which infects many mammalian species and that may cause death. PA binds to a receptor (ATR) in sensitive eukaryotic cells, thereby facilitating the translocation of the enzymatic toxin components, edema factor and lethal factor, across the target cell membrane. PA associated with LF causes death when injected, PA associated with EF produces edema. PA induces immunity to infection with anthrax. 
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== Publication Abstract from PubMed ==
Anthrax toxin, comprising protective antigen, lethal factor, and oedema factor, is the major virulence factor of Bacillus anthracis, an agent that causes high mortality in humans and animals. Protective antigen forms oligomeric prepores that undergo conversion to membrane-spanning pores by endosomal acidification, and these pores translocate the enzymes lethal factor and oedema factor into the cytosol of target cells. Protective antigen is not only a vaccine component and therapeutic target for anthrax infections but also an excellent model system for understanding the mechanism of protein translocation. On the basis of biochemical and electrophysiological results, researchers have proposed that a phi (Phi)-clamp composed of phenylalanine (Phe)427 residues of protective antigen catalyses protein translocation via a charge-state-dependent Brownian ratchet. Although atomic structures of protective antigen prepores are available, how protective antigen senses low pH, converts to active pore, and translocates lethal factor and oedema factor are not well defined without an atomic model of its pore. Here, by cryo-electron microscopy with direct electron counting, we determine the protective antigen pore structure at 2.9-A resolution. The structure reveals the long-sought-after catalytic Phi-clamp and the membrane-spanning translocation channel, and supports the Brownian ratchet model for protein translocation. Comparisons of four structures reveal conformational changes in prepore to pore conversion that support a multi-step mechanism by which low pH is sensed and the membrane-spanning channel is formed.

Atomic structure of anthrax protective antigen pore elucidates toxin translocation.,Jiang J, Pentelute BL, Collier RJ, Zhou ZH Nature. 2015 May 28;521(7553):545-9. doi: 10.1038/nature14247. Epub 2015 Mar 16. PMID:25778700<ref>PMID:25778700</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3j9c" style="background-color:#fffaf0;"></div>

==See Also==
*[[Anthrax protective antigen|Anthrax protective antigen]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Collier, R J]]
[[Category: Jiang, J]]
[[Category: Pentelute, B L]]
[[Category: Zhou, Z H]]
[[Category: Anthrax toxin]]
[[Category: Bacterial toxin]]
[[Category: Protective antigen]]
[[Category: Protein translocation channel]]
[[Category: Toxin]]
[[Category: Transport protein]]