1zkj
From Proteopedia
(New page: 200px<br /><applet load="1zkj" size="350" color="white" frame="true" align="right" spinBox="true" caption="1zkj, resolution 1.55Å" /> '''Structural Basis for...) |
|||
| Line 4: | Line 4: | ||
==Overview== | ==Overview== | ||
| - | The emergence and dissemination of extended-spectrum (ES) beta-lactamases | + | 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== | ==About this Structure== | ||
| Line 14: | Line 14: | ||
[[Category: Enterobacter aerogenes]] | [[Category: Enterobacter aerogenes]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: An, Y | + | [[Category: An, Y J.]] |
| - | [[Category: Cha, S | + | [[Category: Cha, S S.]] |
| - | [[Category: Jung, H | + | [[Category: Jung, H I.]] |
| - | [[Category: Lee, S | + | [[Category: Lee, S H.]] |
[[Category: ACY]] | [[Category: ACY]] | ||
[[Category: ZN]] | [[Category: ZN]] | ||
| Line 25: | Line 25: | ||
[[Category: plasmid]] | [[Category: plasmid]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:16:29 2008'' |
Revision as of 14:16, 21 February 2008
|
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 with and as ligands. Active as Beta-lactamase, with EC number 3.5.2.6 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 Thu Feb 21 16:16:29 2008
