Structure of the Bacillus anthracis dTDP-L-rhamnose-biosynthetic enzyme glucose-1-phosphate thymidylyltransferase (RfbA).Baumgartner, J., Lee, J., Halavaty, A.S., Minasov, G., Anderson, W.F., Kuhn, M.L.
(2017) Acta Crystallogr F Struct Biol Commun 73: 621-628
- PubMed: 29095156
- DOI: 10.1107/S2053230X17015357
- PubMed Abstract:
L-Rhamnose is a ubiquitous bacterial cell-wall component. The biosynthetic pathway for its precursor dTDP-L-rhamnose is not present in humans, which makes the enzymes of the pathway potential drug targets. In this study, the three-dimensional structu ...
L-Rhamnose is a ubiquitous bacterial cell-wall component. The biosynthetic pathway for its precursor dTDP-L-rhamnose is not present in humans, which makes the enzymes of the pathway potential drug targets. In this study, the three-dimensional structure of the first protein of this pathway, glucose-1-phosphate thymidylyltransferase (RfbA), from Bacillus anthracis was determined. In other organisms this enzyme is referred to as RmlA. RfbA was co-crystallized with the products of the enzymatic reaction, dTDP-α-D-glucose and pyrophosphate, and its structure was determined at 2.3 Å resolution. This is the first reported thymidylyltransferase structure from a Gram-positive bacterium. RfbA shares overall structural characteristics with known RmlA homologs. However, RfbA exhibits a shorter sequence at its C-terminus, which results in the absence of three α-helices involved in allosteric site formation. Consequently, RfbA was observed to exhibit a quaternary structure that is unique among currently reported glucose-1-phosphate thymidylyltransferase bacterial homologs. These structural analyses suggest that RfbA may not be allosterically regulated in some organisms and is structurally distinct from other RmlA homologs.
Department of Chemistry and Biochemistry, San Francisco State University, USA.