1zkj
From Proteopedia
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| , resolution 1.55Å | |||||||
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| Ligands: | , | ||||||
| Activity: | Beta-lactamase, with EC number 3.5.2.6 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structural Basis for the Extended Substrate Spectrum of CMY-10, a Plasmid-Encoded Class C beta-lactamase
Overview
The emergence and dissemination of extended-spectrum (ES) beta-lactamases induce therapeutic failure and a lack of eradication of clinical isolates even by third-generation beta-lactam antibiotics like ceftazidime. CMY-10 is a plasmid-encoded class C beta-lactamase with a wide spectrum of substrates. Unlike the well-studied class C ES beta-lactamase from Enterobacter cloacae GC1, the Omega-loop does not affect the active site conformation and the catalytic activity of CMY-10. Instead, a three-amino-acid deletion in the R2-loop appears to be responsible for the ES activity of CMY-10. According to the crystal structure solved at 1.55 A resolution, the deletion significantly widens the R2 active site, which accommodates the R2 side-chains of beta-lactam antibiotics. This observation led us to demonstrate the hydrolysing activity of CMY-10 towards imipenem with a long R2 substituent. The forced mutational analyses of P99 beta-lactamase reveal that the introduction of deletion mutations into the R2-loop is able to extend the substrate spectrum of class C non-ES beta-lactamases, which is compatible with the isolation of natural class C ES enzymes harbouring deletion mutations in the R2-loop. Consequently, the opening of the R2 active site by the deletion of some residues in the R2-loop can be considered as an operative molecular strategy of class C beta-lactamases to extend their substrate spectrum.
About this Structure
1ZKJ is a Single protein structure of sequence from Enterobacter aerogenes. Full crystallographic information is available from OCA.
Reference
Structural basis for the extended substrate spectrum of CMY-10, a plasmid-encoded class C beta-lactamase., Kim JY, Jung HI, An YJ, Lee JH, Kim SJ, Jeong SH, Lee KJ, Suh PG, Lee HS, Lee SH, Cha SS, Mol Microbiol. 2006 May;60(4):907-16. PMID:16677302
Page seeded by OCA on Mon Mar 31 01:37:56 2008
