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| [[Image:1e25.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1e25| PDB=1e25 | SCENE= }} | | {{STRUCTURE_1e25| PDB=1e25 | SCENE= }} |
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| '''THE HIGH RESOLUTION STRUCTURE OF PER-1 CLASS A BETA-LACTAMASE'''
| | ===THE HIGH RESOLUTION STRUCTURE OF PER-1 CLASS A BETA-LACTAMASE=== |
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| ==Overview==
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| The treatment of infectious diseases by beta-lactam antibiotics is continuously challenged by the emergence and dissemination of new beta-lactamases. In most cases, the cephalosporinase activity of class A enzymes results from a few mutations in the TEM and SHV penicillinases. The PER-1 beta-lactamase was characterized as a class A enzyme displaying a cephalosporinase activity. This activity was, however, insensitive to the mutations of residues known to be critical for providing extended substrate profiles to TEM and SHV. The x-ray structure of the protein, solved at 1.9-A resolution, reveals that two of the most conserved features in class A beta-lactamases are not present in this enzyme: the fold of the Omega-loop and the cis conformation of the peptide bond between residues 166 and 167. The new fold of the Omega-loop and the insertion of four residues at the edge of strand S3 generate a broad cavity that may easily accommodate the bulky substituents of cephalosporin substrates. The trans conformation of the 166-167 bond is related to the presence of an aspartic acid at position 136. Selection of class A enzymes based on the occurrence of both Asp(136) and Asn(179) identifies a subgroup of enzymes with high sequence homology.
| | The line below this paragraph, {{ABSTRACT_PUBMED_10825176}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 10825176 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_10825176}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Class a cephalosporinase]] | | [[Category: Class a cephalosporinase]] |
| [[Category: Hydrolase]] | | [[Category: Hydrolase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 14:33:53 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 00:01:03 2008'' |
