Hamasawa K, Kobayashi Y, Harada S, Yoda K, Yamasaki M, Tamura G
Department of Agricultural Chemistry, University of Tokyo, Japan.
J Gen Microbiol. 1987 Apr;133(4):1089-97. doi: 10.1099/00221287-133-4-1089.
A 3-isopropylmalate dehydrogenase (3-IMDH, EC 1.1.1.85) gene was cloned from a gene library of Candida utilis. One of the plasmids, pYKL30, could complement Escherichia coli leuB and Saccharomyces cerevisiae leu2 auxotrophs; a 2.2 kb HindIII fragment subcloned in pBR322 could still complement the leuB mutation. Southern hybridization confirmed that this fragment was derived from C. utilis. An open reading frame of 1089 bp that corresponded to a polypeptide of 363 amino acids, one residue shorter than the 3-IMDH of S. cerevisiae, was found in the cloned fragment. The homology between the 3-IMDHs of C. utilis and S. cerevisiae was 76.2% in nucleotides and 85.4% in amino acids. In contrast, the homology between the 3-IMDHs of C. utilis and Thermus thermophilus was much smaller and was restricted to some regions of the gene.
从产朊假丝酵母的基因文库中克隆出一个3-异丙基苹果酸脱氢酶（3-IMDH，EC 1.1.1.85）基因。其中一个质粒pYKL30能够互补大肠杆菌亮氨酸营养缺陷型菌株和酿酒酵母亮氨酸营养缺陷型菌株；亚克隆到pBR322中的一个2.2 kb HindIII片段仍然能够互补亮氨酸营养缺陷型菌株。Southern杂交证实该片段来源于产朊假丝酵母。在克隆片段中发现了一个1089 bp的开放阅读框，其对应一个由363个氨基酸组成的多肽，比酿酒酵母的3-IMDH少一个残基。产朊假丝酵母和酿酒酵母的3-IMDH在核苷酸水平上的同源性为76.2%，在氨基酸水平上的同源性为85.4%。相比之下，产朊假丝酵母和嗜热栖热菌的3-IMDH之间的同源性要小得多，并且仅限于该基因的某些区域。
