title: Inactivation of bacterial DD-peptidase by beta-sultams.
abstract: N-Acyl-beta-sultams are time-dependent, irreversible active site-directed inhibitors of Streptomyces R61 DD-peptidase. The rate of inactivation is first order with respect to beta-sultam concentration, and the second-order rate constants show a dependence on pH similar to that for the hydrolysis of a substrate. Inactivation is due to the formation of a stable 1:1 enzyme-inhibitor complex as a result of the active site serine being sulfonylated by the beta-sultam as shown by ESI-MS analysis and by X-ray crystallography. A striking feature of the sulfonyl enzyme is that the inhibitor is not bound to the oxyanion hole but interacts extensively with the "roof" of the active site where the Arg 285 is located.
authors.affiliation: Department of Chemical and Biological Sciences, The University of Huddersfield, Huddersfield HD1 3DH, UK.
authors.forename: Antonio
authors.initials: A
authors.lastname: Llinás
authors.forename: Naveed
authors.initials: N
authors.lastname: Ahmed
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Cordaro
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Laws
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Frère
authors.forename: Michael
authors.initials: M
authors.lastname: Delmarcelle
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Silvaggi
authors.forename: Judith A
authors.initials: JA
authors.lastname: Kelly
authors.forename: Michael I
authors.initials: MI
authors.lastname: Page
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry*; D004793:Enzyme Reactivators / Q000737:chemistry; D004795:Enzyme Stability; D004952:Esters; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D019811:Hydroxylamine / Q000737:chemistry; D012694:Serine / Q000737:chemistry; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013302:Streptomyces / Q000201:enzymology / Q000254:growth & development; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D004793:Enzyme Reactivators; D004952:Esters; D013438:Sulfhydryl Compounds; D013449:Sulfonamides; C480101:beta-sultam; D019811:Hydroxylamine; D012694:Serine; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase