1ceg
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(New page: 200px<br /> <applet load="1ceg" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ceg, resolution 1.80Å" /> '''CEPHALOTHIN COMPLEX...)
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Revision as of 18:49, 29 October 2007
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CEPHALOTHIN COMPLEXED WITH DD-PEPTIDASE
Overview
Two clinically-important beta-lactam antibiotics, cephalothin and, cefotaxime, have been observed by X-ray crystallography bound to the, reactive Ser62 of the D-alanyl-D-alanine carboxypeptidase/transpeptidase, of Streptomyces sp. R61. Refinement of the two crystal structures produced, R factors for 3 sigma (F) data of 0.166 (to 1.8 A) and 0.170 (to 2.0 A), for the cephalothin and cefotaxime complexes, respectively. In each, complex, a water molecule is within 3.1 and 3.6 A of the acylated, beta-lactam carbonyl carbon atom, but is poorly activated by active site, residues for nucleophilic attack and deacylation. This apparent lack of, good stereochemistry for facile hydrolysis is in accord with the long, half-lives of cephalosporin intermediates in solution (20-40 h) and the, efficacy of ... [(full description)]
About this Structure
1CEG is a [Single protein] structure of sequence from [Streptomyces sp.] with CEP as [ligand]. Active as [[1]], with EC number [3.4.16.4]. Full crystallographic information is available from [OCA].
Reference
Binding of cephalothin and cefotaxime to D-ala-D-ala-peptidase reveals a functional basis of a natural mutation in a low-affinity penicillin-binding protein and in extended-spectrum beta-lactamases., Kuzin AP, Liu H, Kelly JA, Knox JR, Biochemistry. 1995 Jul 25;34(29):9532-40. PMID:7626623
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