The Acyl-enzyme Mechanism of Beta-lactamase Action. The Evidence for Class C Beta-lactamases
Overview
Authors
Affiliations
Methanol or ethanol can replace water in the action of certain chromosomal beta-lactamases on benzylpenicillin: the products are alpha-methyl or alpha-ethyl benzylpenicilloate. The beta-lactamases were from a mutant of Pseudomonas aeruginosa 18S that produces the enzyme constitutively [Flett, Curtis & Richmond (1976) J. Bacteriol. 127, 1585-1586; Berks, Redhead & Abraham (1982) J. Gen. Microbiol. 128, 155-159] and from Escherichia coli K12 (the ampC beta-lactamase) [Lindström, Boman & Steele (1970) J. Bacteriol. 101, 218-231]. The variation of the rates of alcoholysis and hydrolysis with concentration of alcohol show that the rate-determining step is breakdown of an intermediate. This intermediate is likely to be the acyl-enzyme. The esters, alpha-methyl or alpha-ethyl benzylpenicilloate, are themselves substrates for the Pseudomonas beta-lactamase, benzylpenicilloic acid being formed. Thus this beta-lactamase can be an esterase. The kinetics for the hydrolysis of cloxacillin by the Pseudomonas beta-lactamase are consistent with the acyl-enzyme, formed by acylation of serine-80, being an intermediate in the overall hydrolysis.
Detection of an enzyme isomechanism by means of the kinetics of covalent inhibition.
Adediran S, Morrison M, Pratt R Biochim Biophys Acta Proteins Proteom. 2021; 1869(9):140681.
PMID: 34087495 PMC: 8316153. DOI: 10.1016/j.bbapap.2021.140681.
Ruppe E, Cherkaoui A, Lazarevic V, Emonet S, Schrenzel J Antibiotics (Basel). 2017; 6(4).
PMID: 29186015 PMC: 5745473. DOI: 10.3390/antibiotics6040030.
Molecular Targets of β-Lactam-Based Antimicrobials: Beyond the Usual Suspects.
Konaklieva M Antibiotics (Basel). 2016; 3(2):128-42.
PMID: 27025739 PMC: 4790389. DOI: 10.3390/antibiotics3020128.
Covalent docking predicts substrates for haloalkanoate dehalogenase superfamily phosphatases.
London N, Farelli J, Brown S, Liu C, Huang H, Korczynska M Biochemistry. 2014; 54(2):528-37.
PMID: 25513739 PMC: 4303301. DOI: 10.1021/bi501140k.
Interactions of "bora-penicilloates" with serine β-lactamases and DD-peptidases.
Dzhekieva L, Adediran S, Pratt R Biochemistry. 2014; 53(41):6530-8.
PMID: 25302576 PMC: 4204886. DOI: 10.1021/bi500970f.