Ford R A, Ye Z H, Bhattacharjee J K
Department of Microbiology, Miami University, Oxford, OH 45056.
J Basic Microbiol. 1993;33(3):179-86. doi: 10.1002/jobm.3620330308.
The alpha-aminoadipate pathway for the biosynthesis of lysine is present in yeast and other higher fungi. The lys2 and lys5 mutants of Saccharomyces cerevisiae as well as the lys1- and lys7-mutants of Schizosacharomyces pombe are blocked at the alpha-aminoadipate reductase step of this pathway. The cloned lys1+ gene in the plasmid pLYS1 isolated from a S. pombe genomic library complemented lys1-mutant of S. pombe. The cloned LYS2 gene in the plasmid YEp620 and the LYS5 gene in the plasmid pSC5 of S. cerevisiae exhibited heterologous complementation of lys1- and lys7-mutants, respectively, of S. pombe. The homologous lys1+ transformed cells exhibited five fold higher alpha-aminoadipate reductase activity while the heterologous lys1+ and lys7+ transformed cells exhibited much less activity than the wild type cells. The DNA insert of the plasmid pLYS1 was determined to be 16.7 kb long and the lys1+ gene has been subcloned within a 9.1 kb Clal-Clal DNA insert of the recombinant plasmids pLYS1B and pLYS1C. The restriction pattern for 12 enzymes of the 9.1 kb DNA insert, (Apal, Aval, BamHI, Clal, EcoRI, EcoRV, HindIII, Hpal, Pstl, Pvull, Sphl, and Xbal), exhibited no obvious similarity to that of the LYS2 gene of S. cerevisiae. A 1.7 kb EcoRI-HindIII DNA fragment of pLYS1B and pLYS1C complemented the lys1-131 mutation in an integrative transformation. Although the lys1+ gene of S. pombe is isofunctional to the LYS2 gene of S. cerevisiae, the restriction sites, and expression of these two genes exhibited considerable divergence.
赖氨酸生物合成的α-氨基己二酸途径存在于酵母和其他高等真菌中。酿酒酵母的lys2和lys5突变体以及粟酒裂殖酵母的lys1和lys7突变体在该途径的α-氨基己二酸还原酶步骤受阻。从粟酒裂殖酵母基因组文库中分离出的质粒pLYS1中的克隆lys1 +基因可互补粟酒裂殖酵母的lys1突变体。酿酒酵母质粒YEp620中的克隆LYS2基因和质粒pSC5中的LYS5基因分别对粟酒裂殖酵母的lys1和lys7突变体表现出异源互补。同源lys1 +转化细胞的α-氨基己二酸还原酶活性高五倍，而异源lys1 +和lys7 +转化细胞的活性比野生型细胞低得多。确定质粒pLYS1的DNA插入片段长16.7 kb，并且lys1 +基因已亚克隆到重组质粒pLYS1B和pLYS1C的9.1 kb Clal-Clal DNA插入片段中。9.1 kb DNA插入片段的12种酶（Apal、Aval、BamHI、Clal、EcoRI、EcoRV、HindIII、Hpal、Pstl、Pvull、Sphl和Xbal）的限制性图谱与酿酒酵母的LYS2基因没有明显相似性。pLYS1B和pLYS1C的1.7 kb EcoRI-HindIII DNA片段在整合转化中互补lys1-131突变。尽管粟酒裂殖酵母的lys1 +基因与酿酒酵母的LYS2基因功能相同，但这两个基因的限制性位点和表达表现出相当大的差异。
