Human gut <i>Bacteroides</i> capture vitamin B<sub>12</sub> via cell surface-exposed lipoproteins.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30226189.
- Also identified by DOI 10.7554/eLife.37138 and PMC identifier 6143338.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Human gut <i>Bacteroides</i> use surface-exposed lipoproteins to bind and metabolize complex polysaccharides. Although vitamins and other nutrients are also essential for commensal fitness, much less is known about how commensal bacteria compete with each other or the host for these critical resources. Unlike in <i>Escherichia coli</i>, transport loci for vitamin B<sub>12</sub> (cobalamin) and other corrinoids in human gut <i>Bacteroides</i> are replete with conserved genes encoding proteins whose functions are unknown. Here we report that one of these proteins, BtuG, is a surface-exposed lipoprotein that is essential for efficient B<sub>12</sub> transport in <i>B. thetaiotaomicron.</i> BtuG binds B<sub>12</sub> with femtomolar affinity and can remove B<sub>12</sub> from intrinsic factor, a critical B<sub>12</sub> transport protein in humans. Our studies suggest that <i>Bacteroides</i> use surface-exposed lipoproteins not only for capturing polysaccharides, but also to acquire key vitamins in the gut.
Medical subject headings
- Bacteroides
- Cell Membrane
- Gastrointestinal Tract
- Lipoproteins
- Vitamin B 12