3oex

Publication Abstract from PubMed

Dehydroquinate dehydratase (DHQD) catalyzes the third step in the biosynthetic shikimate pathway. We present three crystal structures of the Salmonella enterica type I DHQD that address the functionality of a surface loop that is observed to close over the active site following substrate binding. Two wild-type structures with differing loop conformations and kinetic and structural studies of a mutant provide evidence of both direct and indirect mechanisms of involvement of the loop in substrate binding. In addition to allowing amino acid side chains to establish a direct interaction with the substrate, closure of the loop necessitates a conformational change of a key active site arginine, which in turn positions the substrate productively. The absence of DHQD in humans and its essentiality in many pathogenic bacteria make the enzyme a target for the development of nontoxic antimicrobials. The structures and ligand binding insights presented here may inform the design of novel type I DHQD inhibiting molecules.

A conserved surface loop in type I dehydroquinate dehydratases positions an active site arginine and functions in substrate binding.,Light SH, Minasov G, Shuvalova L, Peterson SN, Caffrey M, Anderson WF, Lavie A Biochemistry. 2011 Mar 29;50(12):2357-63. Epub 2011 Feb 21. PMID:21291284^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.