title: Identification of a novel UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) from Vibrio fischeri that confers high fosfomycin resistance in Escherichia coli.
abstract: MurA [UDP-N-acetylglucosamine (UDP-NAG) enolpyruvyl transferase] is a key enzyme involved in bacterial cell wall peptidoglycan synthesis and a target for the antimicrobial agent fosfomycin, a structural analog of the MurA substrate phosphoenol pyruvate. In this study, we identified, cloned and sequenced a novel murA gene from an environmental isolate of Vibrio fischeri that is naturally resistant to fosfomycin. The fosfomycin resistance gene was isolated from a genomic DNA library of V. fischeri. An antimicrobial agent hypersensitive strain of Escherichia coli harboring murA from V. fischeri exhibited a high fosfomycin resistance phenotype, with minimum inhibitory concentration of 3,000 microg/ml. The cloned murA gene was 1,269 bp long encoding a 422 amino acid polypeptide with an estimated pI of 5.0. The deduced amino acid sequence of the putative protein was identified as UDP-NAG enolpyruvyl transferase by homology comparison. The MurA protein with an estimated molecular weight of 44.7 kDa was expressed in E. coli and purified by affinity chromatography. MurA of V. fischeri will be a useful target to identify potential inhibitors of fosfomycin resistance in pharmacological studies.
authors.affiliation: Department of Biology, Eastern New Mexico University, Portales NM, 88130, USA.
authors.forename: Sanath
authors.initials: S
authors.lastname: Kumar
authors.forename: Ammini
authors.initials: A
authors.lastname: Parvathi
authors.forename: Ricardo L
authors.initials: RL
authors.lastname: Hernandez
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Cadle
authors.forename: Manuel F
authors.initials: MF
authors.lastname: Varela
mesh_terms: D048908:Aliivibrio fischeri / Q000201:enzymology* / Q000235:genetics; D019883:Alkyl and Aryl Transferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D005578:Fosfomycin / Q000494:pharmacology*; D007526:Isoelectric Point; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D005578:Fosfomycin; D019883:Alkyl and Aryl Transferases; C022566:UDP-N-acetylglucosamine 1-carboxyvinyltransferase