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Effects of Asn152 mutation on substrate selectivity of P99 cephalosporinase
Author(s) -
Ruble James F.,
Tomlinson Jenna M.,
Lefurgy Scott T.,
Cornish Virginia W.,
Powers Rachel A.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.853.10
Subject(s) - mutant , bacteria , enzyme , asparagine , residue (chemistry) , mutation , selectivity , chemistry , biochemistry , antibiotics , substrate (aquarium) , gene , microbiology and biotechnology , biology , genetics , ecology , catalysis
In the past, physicians were able to combat bacterial infection by administration of beta‐lactam antibiotics. These drugs destroy bacteria by disrupting the final stage of cell wall synthesis. Bacteria, however, evolved resistance to these compounds by producing beta‐lactamase enzymes, which hydrolyze the lactam ring and render it inactive. Of major concern are bacteria that have become resistant by acquiring mutations in their beta‐lactamase genes. These mutations alter the selectivity of enzyme for substrate, thereby allowing the mutant enzyme to effectively break apart many different beta‐lactams, either in addition to, or at the expense of, their "preferred substrate". For the enzyme P99 cephalosporinase, it has been shown that mutation of the conserved asparagine residue at position 152 can have a substantial effect on substrate selectivity of the enzyme (Lefurgy, 2007). In this study, a full kinetic characterization of the N152G mutant was performed using several beta‐lactams. Attempts to crystallize the mutant are being performed under published conditions as well as new conditions obtained from high‐throughput screening techniques. Further studies of mutational effects on the Asn152 will help to elicit the detailed structure and function relationship for this residue and could potentially allow researchers to develop improved antibacterial drugs for clinical use.