3OEX : Crystal Structure of Type I 3-Dehydroquinate Dehydratase (aroD) from Salmonella typhimurium with close loop conformation.



Experimental Technique/Method:X-RAY DIFFRACTION
Release Date:2010-09-01
Deposition Date:2010-08-13
Revision Date:2011-07-13#2017-11-08
Molecular Weight:110660.42
Macromolecule Type:Protein
Residue Count:1020
Atom Site Count:7998

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.
Date made available2010

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