TY  - JOUR
N1  - Copyright of this article belongs to ASBMB.
ID  - open1643
UR  - http://www.jbc.org/content/290/18/11293.long
IS  - 18
A1  - Islam, Zeyaul
A1  - Kumar, Adarsh
A1  - Singh, Suruchi
A1  - Salmon, Laurent
A1  - Karthikeyan, Subramanian
Y1  - 2015/05/01/
N2  - The riboflavin biosynthesis pathway has been shown to be essential in many pathogens and is absent in humans. Therefore, enzymes involved in riboflavin synthesis are considered as potential antibacterial drug targets. The enzyme 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) catalyzes one of the two committed steps in the riboflavin pathway and converts d-ribulose 5-phosphate (Ru5P) to l-3,4-dihydroxy-2-butanone 4-phosphate and formate. Moreover, DHBPS is shown to be indispensable for Mycobacterium, Salmonella, and Helicobacter species. Despite the essentiality of this enzyme in bacteria, no inhibitor has been identified hitherto. Here, we describe kinetic and crystal structure characterization of DHBPS from Vibrio cholerae (vDHBPS) with a competitive inhibitor 4-phospho-d-erythronohydroxamic acid (4PEH) at 1.86-Å resolution. In addition, we also report the structural characterization of vDHBPS in its apo form and in complex with its substrate and substrate plus metal ions at 1.96-, 1.59-, and 2.04-Å resolution, respectively. Comparison of these crystal structures suggests that 4PEH inhibits the catalytic activity of DHBPS as it is unable to form a proposed intermediate that is crucial for DHBPS activity. Furthermore, vDHBPS structures complexed with substrate and metal ions reveal that, unlike Candida albicans, binding of substrate to vDHBPS induces a conformational change from an open to closed conformation. Interestingly, the position of second metal ion, which is different from that of Methanococcus jannaschii, strongly supports an active role in the catalytic mechanism. Thus, the kinetic and structural characterization of vDHBPS reveals the molecular mechanism of inhibition shown by 4PEH and that it can be explored further for designing novel antibiotics.
PB  - ASBMB
JF  - The Journal of biological chemistry
VL  - 290
KW  - Crystal Structure; DHBPS; Enzyme Inhibitor; Enzyme Kinetics; Enzyme Mechanism; Riboflavin; Ribulose 5-Phosphate; ribB
SN  - 1083-351X
TI  - Structural basis for competitive inhibition of 3,4-dihydroxy-2-butanone-4-phosphate synthase from Vibrio cholerae.
SP  - 11293
EP  - 308
ER  -