β-Lactamase Inhibition by 7-Alkylidenecephalosporin Sulfones: Allylic Transposition and Formation of An Unprecedented Stabilized Acyl-Enzyme
Document Type
Article
Publication Date
12-11-2013
Publication Title
Journal of The American Chemical Society
Abstract
The inhibition of the class A SHV-1 β-lactamase by 7-(tert-butoxycarbonyl)methylidenecephalosporin sulfone was examined kinetically, spectroscopically, and crystallographically. An 1.14 Å X-ray crystal structure shows that the stable acyl-enzyme, which incorporates an eight-membered ring, is a covalent derivative of Ser70 linked to the 7-carboxy group of 2-H-5,8-dihydro-1,1-dioxo-1,5-thiazocine-4,7-dicarboxylic acid. A cephalosporin-derived enzyme complex of this type is unprecedented, and the rearrangement leading to its formation may offer new possibilities for inhibitor design. The observed acyl-enzyme derives its stability from the resonance stabilization conveyed by the β-aminoacrylate (i.e., vinylogous urethane) functionality as there is relatively little interaction of the eight-membered ring with active site residues. Two mechanistic schemes are proposed, differing in whether, subsequent to acylation of the active site serine and opening of the β-lactam, the resultant dihydrothiazine fragments on its own or is assisted by an adjacent nucleophilic atom, in the form of the carbonyl oxygen of the C7 tert-butyloxycarbonyl group. This compound was also found to be a submicromolar inhibitor of the class C ADC-7 and PDC-3 β-lactamases.
Recommended Citation
Rodkey, Elizabeth A.; Mcleod, David C.; Bethel, Christopher R.; Smith, Kerri M.; Xu, Yan; Chai, Weirui; Che, Tao; Carey, Paul R.; Bonomo, Robert A.; van den Akker, Focco; and Buynak, John D., "β-Lactamase Inhibition by 7-Alkylidenecephalosporin Sulfones: Allylic Transposition and Formation of An Unprecedented Stabilized Acyl-Enzyme" (2013). Chemistry Faculty Publications. 282.
https://engagedscholarship.csuohio.edu/scichem_facpub/282
DOI
10.1021/ja403598g
Volume
135
Issue
49
Comments
J.D.B. acknowledges support from the Robert A. Welch Foundation (grant N-0871). F.v.d.A. acknowledges support of the NIH through grant AI062968. R.A.B. acknowledges support from NIH under award nos. R01AI072219, R01AI063517, and R01AI100560 and by funds and/or facilities provided by the Louis Stokes Cleveland Department of Veterans Affairs Medical Center and the VISN 10 Geriatric Research, Education, and Clinical Care Center (VISN 10) of the Department of Veterans Affairs. P.R.C. acknowledges support from NIH through grant GM54072.