Alberti Adriana, Ferrero Iliana, Lodi Tiziana
Dipartimento di Genetica Antropologia Evoluzione, University of Parma, Italy.
Yeast. 2003 Oct 30;20(14):1171-5. doi: 10.1002/yea.1030.
The KlLYS2 gene, encoding the alpha-aminoadipate reductase of Kluyveromyces lactis, was isolated by complementation of a lysA1 mutant. The deduced amino acid sequence shared an identity of 73% with the LYS2 product of Saccharomyces cerevisiae. Despite the high sequence homology of the alpha-aminoadipate reductase genes, the two yeast species differently responded to the presence of alpha-aminoadipate in the medium. Wild-type S. cerevisiae is known to be sensitive to alpha-aminoadipate, but becomes resistant when mutated to lys2. In contrast, K. lactis strains were found to be naturally resistant to alpha-aminoadipate. Therefore, the positive selection procedure for the isolation of lys2 mutants on alpha-aminoadipate, as practised in S. cerevisiae, cannot be applied to K. lactis. A possible reason of this difference may be that the catalytic rate of the alpha-aminoadipate reductase differs in the two yeasts. The EMBL/Genbank Accession No. for the KlLYS2 gene is AJ504405.
通过对lysA1突变体进行互补，分离出了编码乳酸克鲁维酵母α-氨基己二酸还原酶的KlLYS2基因。推导的氨基酸序列与酿酒酵母的LYS2产物具有73%的同一性。尽管α-氨基己二酸还原酶基因的序列同源性很高，但这两种酵母对培养基中α-氨基己二酸的存在反应不同。已知野生型酿酒酵母对α-氨基己二酸敏感，但突变为lys2时则具有抗性。相反，发现乳酸克鲁维酵母菌株对α-氨基己二酸天然具有抗性。因此，酿酒酵母中用于在α-氨基己二酸上分离lys2突变体的阳性选择程序不能应用于乳酸克鲁维酵母。这种差异的一个可能原因可能是两种酵母中α-氨基己二酸还原酶的催化速率不同。KlLYS2基因的EMBL/Genbank登录号为AJ504405。
