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| {{STRUCTURE_1bza| PDB=1bza | SCENE= }} | | {{STRUCTURE_1bza| PDB=1bza | SCENE= }} |
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- | '''BETA-LACTAMASE TOHO-1 FROM ESCHERICHIA COLI TUH12191'''
| + | ===BETA-LACTAMASE TOHO-1 FROM ESCHERICHIA COLI TUH12191=== |
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- | ==Overview==
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- | Bacterial resistance to beta-lactams is mainly due to the production of beta-lactamase. Especially through the production of extended-spectrum beta-lactamases (ESBLs), bacteria have acquired resistance not only to penicillins, but also to expanded-spectrum cephems. Here, we describe the crystal structure of the E166A mutant of class A beta-lactamase Toho-1 at 1.8 A resolution, the first reported tertiary structure of an ESBL. Instead of the wild-type enzyme, a mutant Toho-1, in which Glu166 was replaced with alanine, was used for this study, because of the strong tendency of the wild-type enzyme to form twinned crystals. The overall structure of Toho-1 is similar to the crystal structures of non-ESBLs, with no pronounced backbone rearrangement of the framework. However, there are some notable local changes. First, a difference in the disposition of an arginine residue, which is at position 244 in non-ESBLs but at position 276 in Toho-1 and other ESBLs, was revealed and the role of this arginine residue is discussed. Moreover, changes in the hydrogen-bonding pattern and in the formation of the hydrophobic core were also observed near the Omega loop. In particular, the lack of hydrogen bonds in the vicinity of the Omega loop could be a cause of the extended substrate specificity of Toho-1. Through the generation of a model for the enzyme-substrate complex, a conformational change of Toho-1 occurring on complex formation is discussed based on the active-site cleft structure and the substrate profile.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9925786}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 9925786 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_9925786}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Beta-lactamase]] | | [[Category: Beta-lactamase]] |
| [[Category: Hydrolase]] | | [[Category: Hydrolase]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 12:08:38 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 19:59:15 2008'' |
Revision as of 16:59, 30 June 2008
Template:STRUCTURE 1bza
BETA-LACTAMASE TOHO-1 FROM ESCHERICHIA COLI TUH12191
Template:ABSTRACT PUBMED 9925786
About this Structure
1BZA is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of the E166A mutant of extended-spectrum beta-lactamase Toho-1 at 1.8 A resolution., Ibuka A, Taguchi A, Ishiguro M, Fushinobu S, Ishii Y, Kamitori S, Okuyama K, Yamaguchi K, Konno M, Matsuzawa H, J Mol Biol. 1999 Feb 5;285(5):2079-87. PMID:9925786
Page seeded by OCA on Mon Jun 30 19:59:15 2008
Categories: Beta-lactamase | Escherichia coli | Single protein | Fushinobu, S. | Ibuka, A. | Ishiguro, M. | Ishii, Y. | Kamitori, S. | Konno, M. | Matsuzawa, H. | Okuyama, K. | Taguchi, A. | Yamaguchi, K. | Hydrolase