8BLW

Vitamin B12 transporter BtuB1 with lipoprotein BtuG1 from B. theta

This is a non-PDB format compatible entry.

Summary for 8BLW

• Entry DOI: 10.2210/pdb8blw/pdb
• Related: 8P97 8P98
• EMDB information: 16114 17574 17575
• Descriptor: Vitamin B12 transporter BtuB1, YncE family protein, beta-D-galactopyranose (3 entities in total)
• Functional Keywords: outer membrane, tonb-dependent transporter, vitamin b12, lipoprotein, membrane protein
• Biological source: Bacteroides thetaiotaomicron VPI-5482; More
• Total number of polymer chains: 2
• Total formula weight: 152289.95

Authors

Silale, A.,Abellon-Ruiz, J.,van den Berg, B. (deposition date: 2022-11-10, release date: 2023-08-16)

Primary citation

Abellon-Ruiz, J.,Jana, K.,Silale, A.,Frey, A.M.,Basle, A.,Trost, M.,Kleinekathofer, U.,van den Berg, B.
BtuB TonB-dependent transporters and BtuG surface lipoproteins form stable complexes for vitamin B 12 uptake in gut Bacteroides.
Nat Commun, 14:4714-4714, 2023

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 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.

PubMed: 37543597
DOI: 10.1038/s41467-023-40427-2

Experimental method

ELECTRON MICROSCOPY (3.22 Å)