Genetic and biochemical characterization of Saccharomyces cerevisiae mutants resistant to trifluoroleucine
Genetic and biochemical characterization of Saccharomyces cerevisiae mutants resistant to trifluoroleucine
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DOI：
10.1016/s0923-2508(97)88085-0
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发表时间：
1997-09-01
影响因子：
2.6
通讯作者：
Polsinelli, M
中科院分区：
文献类型：
--
作者：
Casalone, E;Fia, G;Polsinelli, M
从酿酒酵母（Saccharomycescerevisiae）菌株YNN 281和YNN 282中分离到18株对亮氨酸类似物5 '，5'，5 '-三氟亮氨酸（TFL）具有抗性的突变株。突变体的特点是遗传和聚集在两个组，一个包括所有的显性（TFL 1）和其他一个所有的隐性（TFL 2）突变。遗传和生化数据表明，显性突变位于LEU 4基因，编码α-异丙基苹果酸合酶I。这些突变导致亮氨酸的积累，这是合成对亮氨酸的反馈抑制不敏感的酶的结果。TFL 1突变体的亮氨酸排泄受菌株遗传背景的影响，并受到赖氨酸代谢的极大影响。对携带TFL 1和TFL 2基因的原养型菌株的胞内和胞外氨基酸浓度的测定表明，这两种菌株都是亮氨酸的高产菌株。对TFL 1和TFL 2抗性突变株进行了葡萄汁酒精发酵试验：发酵次级代谢产物分析表明，与亲本菌株相比，TFL 1和TFL 2抗性菌株的主要作用是提高异戊醇的产量。
Eighteen mutants resistant to 5',5',5'-trifluoroleucine (TFL), a leucine analog, were isolated in Saccharomyces cerevisiae strains YNN281 and YNN282. The mutants were characterized genetically and clustered in two groups, one comprising all the dominant (TFL1) and the other one all the recessive (tfl2) mutations. Genetic and biochemical data suggested that the dominant mutations are located on the LEU4 gene, coding for alpha-isopropylmalate synthase I. These mutations resulted in accumulation of leucine as a consequence of the synthesis of an enzyme insensitive to the feedback inhibition by leucine. Leucine excretion in the TFL1 mutants appeared to be affected by the genetic background of the strain and was greatly influenced by lysine metabolism. The measurement of intra-and extracellular amino acid concentrations in prototrophic strains carrying TFL1 or tfl2 genes showed that both were leucine overproducers.Some of the TFL-resistant mutants were tested in alcoholic fermentation of grape must: analysis of the fermentation secondary metabolites showed that the major effect of the TFL-resistant strains was an increased production of isoamyl alcohol compared to that of the parental strain.