title: [Molecular evolution of the sulphite efflux gene SSU1 in Saccharomyces cerevisiae].
abstract: The SSU1 gene encoding a membrane sulfite pump is a main facilitator invovled in sulfite efflux. In Saccharomyce cerevisiae, various range of resistance to sulfite was observed among strains. To explore the evolution traits of SSU1 gene, the population data of S. cerevisiae were collected and analyzed. The phylogenetic analysis indicated that S. cerevisiae population can be classified into three sub-populations, and the positive selection was detected in population by McDonald-Kreitman test. The anaylsis of Ka/Ks ratios further showed that S. cerevisiae sub-population was undergoing positive selection. This finding was also supported by PAML branch model. Nine potential positive selection sites were predicted by branch-site model, and four sites exclusively belong to the sub-population under positive seletion. The data from ssulp protein structure demonstrated that three sites are substitutions between polar and hydrophobic amino acids, and only one site of substitutaion from basic amino acid to basic amino acid (345R/K). Because amino acid pKa values are crucial for sulfite pump to maintain their routine function, positive selection of these amino acid substitutions might affect sulfite efflux efficient.
authors.affiliation: State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning 530007, China. pengpepery@hotmail.com
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning 530007, China.
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning 530007, China.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Non-Food Biomass and Enzyme Technology, National Engineering Research Center for Non-Food Biorefinery, Guangxi Key Laboratory of Biorefinery, Guangxi Academy of Sciences, Nanning 530007, China.
authors.forename: Zhen-Chong
authors.initials: ZC
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D027321:Anion Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D019143:Evolution, Molecular; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012641:Selection, Genetic; D016415:Sequence Alignment; D013447:Sulfites / Q000378:metabolism*; D014920:Wine / Q000382:microbiology
chemical_list: D027321:Anion Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C108311:Ssu1 protein, S cerevisiae; D013447:Sulfites