title: Functional characterization of a putative β-lactamase gene in the genome of Zymomonas mobilis.
abstract: Zymomonas mobilis ZM4 is resistant to β-lactam antibiotics but there are no reports of a β-lactam resistance gene and its regulation. A putative β-lactamase gene sequence (ZMO0103) in the genome of Z. mobilis showed a 55% amino acid sequence identity with class C β-lactamase genes. qPCR analysis of the β-lactamase transcript indicated a higher level expression of the β-lactamase compared to the relative transcript quantities in antibiotic-susceptible bacteria. The putative β-lactamase gene was cloned, expressed in Escherichia coli BL21 and the product, AmpC, was purified to homogeneity. Its optimal activity was at pH 6 and 30 °C. Further, the β-lactamase had a higher affinity towards penicillins than cephalosporin antibiotics.
authors.affiliation: Department of Genetics, Center for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, India. knrmku@gmail.com
authors.forename: K Narayanan
authors.initials: KN
authors.lastname: Rajnish
authors.forename: Sheik Abdul Kader Sheik
authors.initials: SA
authors.lastname: Asraf
authors.forename: Nagarajan
authors.initials: N
authors.lastname: Manju
authors.forename: Paramasamy
authors.initials: P
authors.lastname: Gunasekaran
mesh_terms: D003001:Cloning, Molecular; D004789:Enzyme Activation; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D010406:Penicillins / Q000737:chemistry*; D013379:Substrate Specificity; D017355:Zymomonas / Q000201:enzymology* / Q000235:genetics; D001618:beta-Lactamases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D010406:Penicillins; D001618:beta-Lactamases