4e9j

<StructureSection load='4e9j' size='340' side='right' caption='[[4e9j]], [[Resolution|resolution]] 2.03&Aring;' scene=''>

<table><tr><td colspan='2'>[[4e9j]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa_pao1 Pseudomonas aeruginosa pao1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4E9J OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4E9J FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4ec5|4ec5]]</td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">xcpQ, PA3105 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=208964 Pseudomonas aeruginosa PAO1])</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=4e9j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4e9j OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4e9j RCSB], [http://www.ebi.ac.uk/pdbsum/4e9j PDBsum]</span></td></tr>

== Publication Abstract from PubMed ==

The type II secretion system (T2SS) is a multi-protein assembly spanning the inner and outer-membrane in Gram-negative bacteria. It is found in almost all pathogenic bacteria where it contributes to virulence, host tissue colonization and infection. The exoproteins are secreted across the outer-membrane via a large translocation channel, the secretin, which typically adopts a dodecameric structure. These secretin channels have large periplasmic N-terminal domains that reach out into the periplasm for communication with the inner-membrane platform and with a pseudopilus structure that spans the periplasm. Here we report the crystal structure of the N-terminal periplasmic domain of the secretin XcpQ from Pseudomonas aeruginosa, revealing a two-lobe dimeric assembly featuring parallel subunits engaging in well-defined interactions at the tips of each lobe. We have employed structure-based engineering of disulfide bridges and native mass spectrometry to show that the periplasmic domain of XcpQ dimerizes in a concentration dependent manner. Validation of these insights in the context of cellular full-length XcpQ and further evaluation of the functionality of disulfide-linked XcpQ establishes that the basic oligomerization unit of XcpQ is a dimer. This is consistent with the notion that the dodecameric secretin assembles as a hexamer of dimers to ensure correct projection of the N-terminal domains into the periplasm. Therefore, our studies provide a key conceptual advancement in understanding the assembly principles and dynamic function of T2SS secretins, and challenge recent studies reporting monomers as the basic subunit of the secretin oligomer.

 

== References ==

[[Category: Pseudomonas aeruginosa pao1]]

[[Category: Meeren, R Van der]]

[[Category: Homodimer]]

[[Category: Xcpq]]