TY - JOUR
T1 - Mono- and binuclear Zn2+-β-lactamase. Role of the conserved cysteine in the catalytic mechanism
AU - Paul-Soto, Raquel
AU - Bauer, Rogert
AU - Frère, Jean Marie
AU - Galleni, Moreno
AU - Meyer-Klaucke, Wolfram
AU - Nolting, Hans
AU - Rossolini, Gian Maria
AU - De Seny, Dominique
AU - Hernandez-Valladares, Maria
AU - Zeppezauer, Michael
AU - Adolph, Hans Werner
PY - 1999/5/7
Y1 - 1999/5/7
N2 - When expressed by pathogenic bacteria, Zn2+-β-lactamases induce resistance to most β-lactam antibiotics. A possible strategy to fight these bacteria would be a combined therapy with non-toxic inhibitors of Zn2+-β- lactamases together with standard antibiotics. For this purpose, it is important to verify that the inhibitor is effective under all clinical conditions. We have investigated the correlation between the number of zinc ions bound to the Zn2+-β-lactamase from Bacillus cereus and hydrolysis of benzylpenicillin and nitrocefin for the wild type and a mutant where cysteine 168 is replaced by alanine. It is shown that both the mono-Zn2+ (mononuclear) and di-Zn2+ (binuclear) Zn2+-β-lactamases are catalytically active but with different kinetic properties. The mono-Zn2+- β-lactamase requires the conserved cysteine residue for hydrolysis of the β-lactam ring in contrast to the binuclear enzyme where the cysteine residue is not essential. Substrate affinity is not significantly affected by the mutation for the mononuclear enzyme but is decreased for the binuclear enzyme. These results were derived from kinetic studies on two wild types and the mutant enzyme with benzylpenicillin and nitrocefin as substrates. Thus, targeting drug design to modify this residue might represent an efficient strategy, the more so if it also interferes with the formation of the binuclear enzyme.
AB - When expressed by pathogenic bacteria, Zn2+-β-lactamases induce resistance to most β-lactam antibiotics. A possible strategy to fight these bacteria would be a combined therapy with non-toxic inhibitors of Zn2+-β- lactamases together with standard antibiotics. For this purpose, it is important to verify that the inhibitor is effective under all clinical conditions. We have investigated the correlation between the number of zinc ions bound to the Zn2+-β-lactamase from Bacillus cereus and hydrolysis of benzylpenicillin and nitrocefin for the wild type and a mutant where cysteine 168 is replaced by alanine. It is shown that both the mono-Zn2+ (mononuclear) and di-Zn2+ (binuclear) Zn2+-β-lactamases are catalytically active but with different kinetic properties. The mono-Zn2+- β-lactamase requires the conserved cysteine residue for hydrolysis of the β-lactam ring in contrast to the binuclear enzyme where the cysteine residue is not essential. Substrate affinity is not significantly affected by the mutation for the mononuclear enzyme but is decreased for the binuclear enzyme. These results were derived from kinetic studies on two wild types and the mutant enzyme with benzylpenicillin and nitrocefin as substrates. Thus, targeting drug design to modify this residue might represent an efficient strategy, the more so if it also interferes with the formation of the binuclear enzyme.
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U2 - 10.1074/jbc.274.19.13242
DO - 10.1074/jbc.274.19.13242
M3 - Article
C2 - 10224083
AN - SCOPUS:0033531792
VL - 274
SP - 13242
EP - 13249
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 19
ER -