1iyp: Difference between revisions

Revision as of 20:35, 2 May 2008

Toho-1 beta-Lactamase In Complex With Cephalothin

OverviewOverview

Bacterial resistance to beta-lactam antibiotics is a serious problem limiting current clinical therapy. The most common form of resistance is the production of beta-lactamases that inactivate beta-lactam antibiotics. Toho-1 is an extended-spectrum beta-lactamase that has acquired efficient activity not only to penicillins but also to cephalosporins including the expanded-spectrum cephalosporins that were developed to be stable in former beta-lactamases. We present the acyl-intermediate structures of Toho-1 in complex with cefotaxime (expanded-spectrum cephalosporin), cephalothin (non-expanded-spectrum cephalosporin), and benzylpenicillin at 1.8-, 2.0-, and 2.1-A resolutions, respectively. These structures reveal distinct features that can explain the ability of Toho-1 to hydrolyze expanded-spectrum cephalosporins. First, the Omega-loop of Toho-1 is displaced to avoid the steric contacts with the bulky side chain of cefotaxime. Second, the conserved residues Asn(104) and Asp(240) form unique interactions with the bulky side chain of cefotaxime to fix it tightly. Finally, the unique interaction between the conserved Ser(237) and cephalosporins probably helps to bring the beta-lactam carbonyl group to the suitable position in the oxyanion hole, thus increasing the cephalosporinase activity.

About this StructureAbout this Structure

1IYP is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

Acyl-intermediate structures of the extended-spectrum class A beta-lactamase, Toho-1, in complex with cefotaxime, cephalothin, and benzylpenicillin., Shimamura T, Ibuka A, Fushinobu S, Wakagi T, Ishiguro M, Ishii Y, Matsuzawa H, J Biol Chem. 2002 Nov 29;277(48):46601-8. Epub 2002 Sep 8. PMID:12221102 Page seeded by OCA on Fri May 2 20:35:38 2008

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OCA

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 [[Image:1iyp.jpg|left|200px]]
- {{Structure
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+The line below this paragraph, containing "STRUCTURE_1iyp", creates the "Structure Box" on the page.
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+You may change the PDB parameter (which sets the PDB file loaded into the applet)
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-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Beta-lactamase Beta-lactamase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.2.6 3.5.2.6] </span>
+or leave the SCENE parameter empty for the default display.
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-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1iyp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iyp OCA], [http://www.ebi.ac.uk/pdbsum/1iyp PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1iyp RCSB]</span>
-}}
 '''Toho-1 beta-Lactamase In Complex With Cephalothin'''
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 [[Category: Shimamura, T.]]
 [[Category: Wakagi, T.]]
-[[Category: acyl-enzyme]]
+[[Category: Acyl-enzyme]]
-[[Category: beta-lactamase]]
+[[Category: Beta-lactamase]]
-[[Category: cephalothin]]
+[[Category: Cephalothin]]
-[[Category: complex]]
+[[Category: Complex]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 20:35:38 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:26:31 2008''