title: Exploitation of structural and regulatory diversity in glutamate racemases.
abstract: Glutamate racemase is an enzyme essential to the bacterial cell wall biosynthesis pathway, and has therefore been considered as a target for antibacterial drug discovery. We characterized the glutamate racemases of several pathogenic bacteria using structural and biochemical approaches. Here we describe three distinct mechanisms of regulation for the family of glutamate racemases: allosteric activation by metabolic precursors, kinetic regulation through substrate inhibition, and D-glutamate recycling using a d-amino acid transaminase. In a search for selective inhibitors, we identified a series of uncompetitive inhibitors specifically targeting Helicobacter pylori glutamate racemase that bind to a cryptic allosteric site, and used these inhibitors to probe the mechanistic and dynamic features of the enzyme. These structural, kinetic and mutational studies provide insight into the physiological regulation of these essential enzymes and provide a basis for designing narrow-spectrum antimicrobial agents.
authors.affiliation: AstraZeneca Global Structural Chemistry, AstraZeneca R&D Mölndal, SE-431 83, Mölndal, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Lundqvist
authors.forename: Stewart L
authors.initials: SL
authors.lastname: Fisher
authors.forename: Gunther
authors.initials: G
authors.lastname: Kern
authors.forename: Rutger H A
authors.initials: RH
authors.lastname: Folmer
authors.forename: Yafeng
authors.initials: Y
authors.lastname: Xue
authors.forename: D Trevor
authors.initials: DT
authors.lastname: Newton
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Keating
authors.forename: Richard A
authors.initials: RA
authors.lastname: Alm
authors.forename: Boudewijn L M
authors.initials: BL
authors.lastname: de Jonge
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000495:Allosteric Site / Q000187:drug effects; D000591:Amino Acid Isomerases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology; D001419:Bacteria / Q000201:enzymology* / Q000472:pathogenicity; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology; D016480:Helicobacter pylori / Q000201:enzymology; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D011994:Recombinant Proteins; D000591:Amino Acid Isomerases; C062292:glutamate racemase