4znb
From Proteopedia
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[[Category: metallo beta-lactamase]] | [[Category: metallo beta-lactamase]] | ||
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Revision as of 15:43, 30 October 2007
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METALLO-BETA-LACTAMASE (C181S MUTANT)
Overview
The metallo-beta-lactamases require divalent cations such as zinc or, cadmium for hydrolyzing the amide bond of beta-lactam antibiotics. The, crystal structure of the Zn2+ -bound enzyme from Bacteroides fragilis, contains a binuclear zinc center in the active site. A hydroxide, coordinated to both zinc atoms, is proposed as the moiety that mounts the, nucleophilic attack on the carbonyl carbon atom of the beta-lactam bond of, the substrate. It was previously reported that the replacement of the, active site Cys181 by a serine residue severely impaired catalysis while, atomic absorption measurements indicated that binding of the two zinc ions, remained intact. Contradicting data emerge from recent mass spectrometry, results, which show that only a single zinc ion binds to the C181S, ... [(full description)]
About this Structure
4ZNB is a [Single protein] structure of sequence from [Bacteroides fragilis] with ZN and NA as [ligands]. Active as [Beta-lactamase], with EC number [3.5.2.6]. Structure known Active Sites: NAA, NAB, ZNA and ZNB. Full crystallographic information is available from [OCA].
Reference
Structural consequences of the active site substitution Cys181 ==> Ser in metallo-beta-lactamase from Bacteroides fragilis., Li Z, Rasmussen BA, Herzberg O, Protein Sci. 1999 Jan;8(1):249-52. PMID:10210203
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