View source for 9qpm


==BtuJ1 (BT_1491) bound to cyanocobalamin==
<StructureSection load='9qpm' size='340' side='right'caption='[[9qpm]], [[Resolution|resolution]] 1.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9qpm]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacteroides_thetaiotaomicron_VPI-5482 Bacteroides thetaiotaomicron VPI-5482]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9QPM OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9QPM 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]] 1.4&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CNC:CO-CYANOCOBALAMIN'>CNC</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=9qpm FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9qpm OCA], [https://pdbe.org/9qpm PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9qpm RCSB], [https://www.ebi.ac.uk/pdbsum/9qpm PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9qpm ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q8A7N3_BACTN Q8A7N3_BACTN] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The acquisition of vitamin B(12) and related cobamides is a key determinant for the fitness of Bacteroidota in the gut. Depending on the species, this uptake process relies on one to four transport systems centered on conserved core outer membrane (OM) complexes composed of the TonB-dependent transporter BtuB and the surface-exposed lipoprotein BtuG. Additionally, the surface-exposed lipoprotein BtuH, although not tightly associated with the BtuBG complex, contributes to cobamide uptake and provides a fitness advantage. Here, we report the functional and structural characterization of BtuJ1 from Bacteroides thetaiotaomicron (B. theta), an additional surface-exposed lipoprotein in B(12) uptake loci. BtuJ1 binds vitamin B(12) and cobinamide (an intermediate in B(12) biosynthesis) with low nM affinity, conferring a fitness advantage in B(12)-limited environments. Regardless of B(12) availability, BtuJ1 is the most abundant of the B(12)-transport components encoded by B. theta. Under B(12)-replete conditions, BtuJ1 binds the vitamin, generating a readily available pool for transfer to the core BtuBG transport systems during periods of B(12) depletion as demonstrated by in vitro and in vivo B(12) transfer experiments. Together, these findings expand the known functionalities of the diverse accessory OM proteins employed by Bacteroidota and underscore the sophisticated strategies these human gut commensals use to secure vitamin B(12) in the competitive environment of the human gut.

BtuJ1, a surface-exposed B(12)-binding protein in Bacteroidota, functions as an extracellular vitamin reservoir that enhances fitness.,Abellon-Ruiz J, Pacheco-Gomez R, Watts J, Hart A, Hirt RP, Basle A, van den Berg B J Mol Biol. 2026 Mar 12:169754. doi: 10.1016/j.jmb.2026.169754. PMID:41831674<ref>PMID:41831674</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9qpm" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bacteroides thetaiotaomicron VPI-5482]]
[[Category: Large Structures]]
[[Category: Abellon-Ruiz J]]
[[Category: Van den Berg B]]