Merck

Inhibition of OXA-1 beta-lactamase by penems.

Antimicrobial agents and chemotherapy (2008-06-19)
Christopher R Bethel, Anne M Distler, Mark W Ruszczycky, Marianne P Carey, Paul R Carey, Andrea M Hujer, Magda Taracila, Marion S Helfand, Jodi M Thomson, Matthew Kalp, Vernon E Anderson, David A Leonard, Kristine M Hujer, Takao Abe, Aranapakam M Venkatesan, Tarek S Mansour, Robert A Bonomo
ABSTRACT

The partnering of a beta-lactam with a beta-lactamase inhibitor is a highly effective strategy that can be used to combat bacterial resistance to beta-lactam antibiotics mediated by serine beta-lactamases (EC 3.2.5.6). To this end, we tested two novel penem inhibitors against OXA-1, a class D beta-lactamase that is resistant to inactivation by tazobactam. The K(i) of each penem inhibitor for OXA-1 was in the nM range (K(i) of penem 1, 45 +/- 8 nM; K(i) of penem 2, 12 +/- 2 nM). The first-order rate constant for enzyme and inhibitor complex inactivation of penems 1 and 2 for OXA-1 beta-lactamase were 0.13 +/- 0.01 s(-1) and 0.11 +/- 0.01 s(-1), respectively. By using an inhibitor-to-enzyme ratio of 1:1, 100% inactivation was achieved in <or=900 s and the recovery of OXA-1 beta-lactamase activity was not detected at 24 h. Covalent adducts of penems 1 and 2 (changes in molecular masses, +306 +/- 3 and +321 +/- 3 Da, respectively) were identified by electrospray ionization mass spectrometry (ESI-MS). After tryptic digestion of OXA-1 inactivated by penems 1 and 2, ESI-MS and matrix-assisted laser desorption ionization-time-of-flight MS identified the adducts of 306 +/- 3 and 321 +/- 3 Da attached to the peptide containing the active-site Ser67. The base hydrolysis of penem 2, monitored by serial (1)H nuclear magnetic resonance analysis, suggested that penem 2 formed a linear imine species that underwent 7-endo-trig cyclization to ultimately form a cyclic enamine, the 1,4-thiazepine derivative. Susceptibility testing demonstrated that the penem inhibitors at 4 mg/liter effectively restored susceptibility to piperacillin. Penem beta-lactamase inhibitors which demonstrate high affinities and which form long-lived acyl intermediates may prove to be extremely useful against the broad range of inhibitor-resistant serine beta-lactamases present in gram-negative bacteria.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, protease free, fatty acid free, essentially globulin free, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, BioReagent, suitable for cell culture
Sigma-Aldrich
IPTG, ≥99% (TLC), ≤0.1% Dioxane
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, fatty acid free, low endotoxin, lyophilized powder, BioReagent, suitable for cell culture, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, protease free, essentially globulin free, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, cold ethanol fraction, pH 5.2, ≥96%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, essentially fatty acid free, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, protease free, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, essentially globulin free, ≥99% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, lyophilized powder, essentially fatty acid free, ≥98% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, suitable for (for molecular biology), Non-acetylated
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, suitable for RIA, pH 5.2, ≥96%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, pH 5.2, ≥96%
Sigma-Aldrich
异丙 β-D-1-硫代半乳糖苷, ≥99% (TLC)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, crystallized, ≥98.0% (GE)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, protease free, suitable for hybridization, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, Cohn Fraction V, lyophilized powder, ≥96% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, powder, BioXtra
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, essentially IgG-free, low endotoxin, BioReagent, suitable for cell culture
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, pH 5.2, ≥96%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, low endotoxin, Cohn Analog, BioReagent, suitable for cell culture, ≥98% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, 1× crystallized, ≥97% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, essentially fatty acid free and essentially globulin free, ≥99% (agarose gel electrophoresis)
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, heat shock fraction, protease free, low endotoxin, suitable for cell culture, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, pH <5.0, powder
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, chromatographically purified, New Zealand origin, low endotoxin, suitable for cell culture, pH 7, ≥98%
Sigma-Aldrich
牛血清白蛋白 来源于牛血清, lyophilized powder, essentially globulin free, BioReagent, suitable for cell culture