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-Structure paper
Title | BtuB TonB-dependent transporters and BtuG surface lipoproteins form stable complexes for vitamin B uptake in gut Bacteroides. |
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Journal, issue, pages | Nat Commun, Vol. 14, Issue 1, Page 4714, Year 2023 |
Publish date | Aug 5, 2023 |
Authors | Javier Abellon-Ruiz / Kalyanashis Jana / Augustinas Silale / Andrew M Frey / Arnaud Baslé / Matthias Trost / Ulrich Kleinekathöfer / Bert van den Berg / |
PubMed Abstract | Vitamin B (cobalamin) is required for most human gut microbes, many of which are dependent on scavenging to obtain this vitamin. Since bacterial densities in the gut are extremely high, competition ...Vitamin B (cobalamin) is required for most human gut microbes, many of which are dependent on scavenging to obtain this vitamin. Since bacterial densities in the gut are extremely high, competition for this keystone micronutrient is severe. Contrasting with Enterobacteria, members of the dominant genus Bacteroides often encode several BtuB vitamin B outer membrane transporters together with a conserved array of surface-exposed B-binding lipoproteins. Here we show that the BtuB transporters from Bacteroides thetaiotaomicron form stable, pedal bin-like complexes with surface-exposed BtuG lipoprotein lids, which bind B with high affinities. Closing of the BtuG lid following B capture causes destabilisation of the bound B by a conserved BtuB extracellular loop, causing translocation of the vitamin to BtuB and subsequent transport. We propose that TonB-dependent, lipoprotein-assisted small molecule uptake is a general feature of Bacteroides spp. that is important for the success of this genus in colonising the human gut. |
External links | Nat Commun / PubMed:37543597 / PubMed Central |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 1.33 - 3.72 Å |
Structure data | EMDB-16114, PDB-8blw: EMDB-17574, PDB-8p97: EMDB-17575, PDB-8p98: PDB-8bmx: PDB-8bmy: PDB-8bmz: PDB-8bn0: PDB-8okv: |
Chemicals | ChemComp-GAL: ChemComp-CNC: ChemComp-CL: ChemComp-SO4: ChemComp-HOH: ChemComp-B1Z: ChemComp-CYN: ChemComp-CBY: |
Source |
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Keywords | MEMBRANE PROTEIN / Outer membrane / TonB-dependent transporter / vitamin B12 / lipoprotein / Vitamin B12 Transport Complex Outer membrane / beta propeller surface protein B12 binding protein / Beta propeller Vitamin B12 binding Surface protein / Surface exposed protein Beta propeller Vitamin B12 binding protein / membrane associated / beta propeller / B12 binding protein / Cyanocobalamin / transporter / complex |