Linked Life Data

19672877

Source:http://linkedlifedata.com/resource/pubmed/id/19672877

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2009-9-30
pubmed:abstractText
A large number of beta-lactamases have emerged that are capable of conferring bacterial resistance to beta-lactam antibiotics. Comparison of the structural and functional features of this family has refined understanding of the catalytic properties of these enzymes. An arginine residue present at position 244 in TEM-1 beta-lactamase interacts with the carboxyl group common to penicillin and cephalosporin antibiotics and thereby stabilizes both the substrate and transition state complexes. A comparison of class A beta-lactamase sequences reveals that arginine at position 244 is not conserved, although a positive charge at this structural location is conserved and is provided by an arginine at positions 220 or 276 for those enzymes lacking arginine at position 244. The plasticity of the location of positive charge in the beta-lactamase active site was experimentally investigated by relocating the arginine at position 244 in TEM-1 beta-lactamase to positions 220, 272, and 276 by site-directed mutagenesis. Kinetic analysis of the engineered beta-lactamases revealed that removal of arginine 244 by alanine mutation reduced catalytic efficiency against all substrates tested and restoration of an arginine at positions 272 or 276 partially suppresses the catalytic defect of the Arg244Ala substitution. These results suggest an evolutionary mechanism for the observed divergence of the position of positive charge in the active site of class A beta-lactamases.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1469-896X
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2080-9
pubmed:dateRevised
2010-10-4
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Analysis of the plasticity of location of the Arg244 positive charge within the active site of the TEM-1 beta-lactamase.
pubmed:affiliation
Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural