title: The formation of cyclopropane fatty acids in Salmonella enterica serovar Typhimurium.
abstract: The formation of cyclopropane fatty acid (CFA) and its role in the acid shock response in Salmonella enterica serovar Typhimurium (S. typhimurium) was investigated. Data obtained by GC/MS demonstrated that the CFA level in S. typhimurium increased upon its entry to the stationary phase, as in other bacteria. The cfa gene encoding CFA synthase was cloned, and mutants of the cfa gene were constructed by allelic exchange. A cfa mutant could not produce CFA and was sensitive to low pH. Introduction of a functional cfa gene into a cfa mutant cell made the mutant convert all unsaturated fatty acids to CFAs and partially restored resistance to low pH. Interestingly, the alternative sigma factor RpoS, which was induced during the stationary phase, affected the production of C(19) CFA but not C(17) CFA. Western blotting analysis showed that the increase in expression of CFA synthase at early stationary phase was due to the alternative sigma factor RpoS.
authors.affiliation: Laboratory of Microbial Genetics, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Bae Hoon
authors.initials: BH
authors.lastname: Kim
authors.affiliation: Bioanalysis and Biotransformation Research Center, Korea Institute of Science and Technology, Seoul 136-791, Korea.|Laboratory of Microbial Genetics, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Seungki
authors.initials: S
authors.lastname: Kim
authors.affiliation: Laboratory of Microbial Genetics, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Hyeon Guk
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Laboratory of Microbial Genetics, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Jin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Microbiology, Hannam University, DaeJeon 300-791, Korea.
authors.forename: In Soo
authors.initials: IS
authors.lastname: Lee
authors.affiliation: Laboratory of Microbial Genetics, School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Yong Keun
authors.initials: YK
authors.lastname: Park
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003521:Cyclopropanes; D005227:Fatty Acids / Q000096:biosynthesis*; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006863:Hydrogen-Ion Concentration; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D012486:Salmonella typhimurium / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D017422:Sequence Analysis, DNA; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003521:Cyclopropanes; D005227:Fatty Acids; D012808:Sigma Factor; C028775:cyclopropane fatty acids; C069567:sigma factor KatF protein, Bacteria; D008780:Methyltransferases; C019964:cyclopropane synthetase