title: Cloning and nucleotide sequence of the gene (citA) encoding a citrate carrier from Salmonella typhimurium.
abstract: A cryptic citrate transport gene (citA) from Salmonella typhimurium chromosome was cloned and its nucleotide sequence was determined. The cloned plasmid conferred citrate-utilizing ability on wild-type Escherichia coli, which cannot grow on citrate as the sole source of carbon. The resultant E. coli transformant was able to transport citrate. A 1,302-base-pair open reading frame with a preceding ribosomal binding site was found in the cloned DNA fragment. The 434-amino-acid protein that could be translated from this open reading frame is highly hydrophobic (69% nonpolar amino acid residues), consistent with the fact that the transport protein is an intrinsic membrane protein. The molecular weight of this protein was calculated to be 47,188. The gene sequence determined is highly homologous to those of Cit+ plasmid-mediated citrate transport gene, citA, from E. coli, the chromosomal citA gene from Citrobacter amalonaticus and the chromosomal cit+ gene from Klebsiella pneumoniae. The hydropathy profile of the deduced amino acid sequence suggests that this carrier has 12 hydrophobic segments, which may span the membrane lipid bilayer.
authors.affiliation: Gene Research Center, Okayama University.
authors.forename: T
authors.initials: T
authors.lastname: Shimamoto
authors.forename: H
authors.initials: H
authors.lastname: Izawa
authors.forename: H
authors.initials: H
authors.lastname: Daimon
authors.forename: N
authors.initials: N
authors.lastname: Ishiguro
authors.forename: M
authors.initials: M
authors.lastname: Shinagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Sakano
authors.forename: M
authors.initials: M
authors.lastname: Tsuda
authors.forename: T
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D002951:Citrates / Q000378:metabolism; D019343:Citric Acid; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
chemical_list: D002352:Carrier Proteins; D002951:Citrates; D004269:DNA, Bacterial; D012329:RNA, Bacterial; C020723:citrate-binding transport protein; D019343:Citric Acid