title: Molecular cloning, characterization, and nucleotide sequence of the rfc gene, which encodes an O-antigen polymerase of Salmonella typhimurium.
abstract: The rfc gene of Salmonella typhimurium was located in a 1.75-kb HindIII fragment and restored wild-type lipopolysaccharide synthesis ability to both an older rfc point mutant and new rfc::IS10 mutants. DNA sequencing of the HindIII fragment revealed an open reading frame which could encode a protein of 407 amino acids with an Mr of 47,472 and also revealed potential translation signals. Modulator codons accounted for 12.5% of the total codon content, providing a possible explanation for the nondetectability of the protein in subcellular systems. Secondary structure analysis suggested the presence of transmembrane beta-sheet structures, implying a possible role for the protein in translocation of hydrophilic O-antigen-containing materials. Salmonella strains of groups A, B, and D1 contained rfc-homologous DNA, but strains of groups C1, C2, C3, D2, and E2 did not.
authors.affiliation: Department of Microbiology, University of Adelaide, South Australia.
authors.forename: L V
authors.initials: LV
authors.lastname: Collins
authors.forename: J
authors.initials: J
authors.lastname: Hackett
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon; D004591:Electrophoresis, Polyacrylamide Gel; D005798:Genes, Bacterial; D006602:Hexosyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D019081:O Antigens; D016366:Open Reading Frames; D015183:Restriction Mapping; D012486:Salmonella typhimurium / Q000235:genetics*
chemical_list: D000942:Antigens, Bacterial; D003062:Codon; D019081:O Antigens; D006602:Hexosyltransferases; C068252:O-antigen polymerase, Salmonella