title: Cloning and sequence analysis demonstrate the chromate reduction ability of a novel chromate reductase gene fromSerratiasp.
abstract: The ChrT gene encodes a chromate reductase enzyme which catalyzes the reduction of Cr(VI). The chromate reductase is also known as flavin mononucleotide (FMN) reductase (FMN_red). The aim of the present study was to clone the full-length ChrT DNA fromSerratiasp. CQMUS2 and analyze the deduced amino acid sequence and three-dimensional structure. The putative ChrT gene fragment ofSerratiasp. CQMUS2 was isolated by polymerase chain reaction (PCR), according to the known FMN_red gene sequence fromSerratiasp. AS13. The flanking sequences of the ChrT gene were obtained by high efficiency TAIL-PCR, while the full-length gene of ChrT was cloned inEscherichia colifor subsequent sequencing. The nucleotide sequence of ChrT was submitted onto GenBank under the accession number, KF211434. Sequence analysis of the gene and amino acids was conducted using the Basic Local Alignment Search Tool, and open reading frame (ORF) analysis was performed using ORF Finder software. The ChrT gene was found to be an ORF of 567 bp that encodes a 188-amino acid enzyme with a calculated molecular weight of 20.4 kDa. In addition, the ChrT protein was hypothesized to be an NADPH-dependent FMN_red and a member of the flavodoxin-2 superfamily. The amino acid sequence of ChrT showed high sequence similarity to the FMN reductase genes ofKlebsiella pneumoniaandRaoultella ornithinolytica, which belong to the flavodoxin-2 superfamily. Furthermore, ChrT was shown to have a 85.6% similarity to the three-dimensional structure ofEscherichia coliChrR, sharing four common enzyme active sites for chromate reduction. Therefore, ChrT gene cloning and protein structure determination demonstrated the ability of the gene for chromate reduction. The results of the present study provide a basis for further studies on ChrT gene expression and protein function.
authors: Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China.
authors: Peng
authors: P
authors: Deng
authors: Physical Examination Center, Third People's Hospital of Chongqing, Chongqing 401121, P.R. China.
authors: Xiaoqing
authors: X
authors: Tan
authors: Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China.
authors: Ying
authors: Y
authors: Wu
authors: Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China.
authors: Qunhua
authors: Q
authors: Bai
authors: Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China.
authors: Yan
authors: Y
authors: Jia
authors: Department of Occupational and Environmental Health, College of Public Health and Administration, Chongqing Medical University, Chongqing 400016, P.R. China.
authors: Hong
authors: H
authors: Xiao
keywords: Serratia sp.; chromate reductase; flavin mononucleotide reductase; gene cloning; sequence analysis