title: Molecular identification of an arsenic four-gene operon in Campylobacter lari.
abstract: An arsenic (ars) four-gene operon, containing genes encoding a putative membrane permease (ArsP), a transcriptional repressor (ArsR), an arsenate reductase (ArsC) and an arsenical-resistance membrane transporter (Acr3) was first identified in urease-positive thermophilic Campylobacter (UPTC) isolate, CF89-12. UPTC CF89-12 and some other Campylobacter lari isolates contained their ars four-genes, similarly, differing from that in the reference C. lari RM2100 strain. Two putative promoters and a putative terminator were identified for the operon in UPTC CF89-12. In vivo transcription of the operon was confirmed in the UPTC cells. PCR experiments using two primer pairs designed in silico to amplify two arsR and arsC-acr3 segments, respectively, generated two amplicons, approximately 200 and 350 base pairs, with all 31 of 31 and 19 of 31 C. lari isolates (n = 17 for UPTC; n = 14 for UN C. lari), respectively. An inverted repeat forming a dyad structure, a potential binding site for a transcriptional repressor, was identified in the promoter region. Within the deduced 61 amino acids sequence of the putative arsR open reading frame from the UPTC CF89-12, a metal binding box and a DNA-binding helix-turn-helix motif were identified. The UPTC CF89-12 and some other UPTC isolates isolated from natural environment were resistant to arsenate.
authors.affiliation: Laboratory of Molecular Biology, Graduate School of Environmental Health Sciences, Azabu University, Sagamihara 252-5201, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.forename: R
authors.initials: R
authors.lastname: Nagatomi
authors.forename: K
authors.initials: K
authors.lastname: Matsubara
authors.forename: J E
authors.initials: JE
authors.lastname: Moore
authors.forename: B C
authors.initials: BC
authors.lastname: Millar
authors.forename: M
authors.initials: M
authors.lastname: Matsuda
mesh_terms: D000595:Amino Acid Sequence; D053502:Arsenate Reductases / Q000235:genetics; D001151:Arsenic; D044863:Campylobacter lari / Q000235:genetics* / Q000302:isolation & purification; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D056426:Genetic Loci; D019077:Helix-Turn-Helix Motifs / Q000235:genetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D009876:Operon / Q000235:genetics*; D012329:RNA, Bacterial / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014510:Urease / Q000235:genetics
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D053502:Arsenate Reductases; D014510:Urease; D001151:Arsenic