Kotrbova-Kozak Anna, Kotrba Pavel, Inui Masayuki, Sajdok Jiri, Yukawa Hideaki
Research Institute of Innovative Technology for the Earth, 9-2, Kizugawadai, Kizugawa, Kyoto 619-0292, Japan.
Appl Microbiol Biotechnol. 2007 Oct;76(6):1347-56. doi: 10.1007/s00253-007-1094-6. Epub 2007 Jul 24.
Corynebacterium glutamicum R adhA gene encodes a homodimeric, NAD-dependent, 345 amino acid residue alcohol dehydrogenase with two zinc ions per subunit. Chromosomal inactivation of the adhA gene rendered the strain incapable of growth on either ethanol or n-propanol as the sole carbon source. RNA hybridization analysis revealed that adhA transcription was not only induced by these two substrates, but it was also subject to glucose catabolite repression. Accordingly, both induction of AdhA activity and ethanol utilization were detected only after depletion of glucose. Deletion of either or both of potential cyclic adenosine monophosphate (cAMP) receptor binding site and an inverted repeat of sequence 5'-GCAATTGATG-N (8)-CACAATTGC-3' in the promoter region of adhA strongly suggested that IR, which does not share significant similarity with other regulatory DNA elements of C. glutamicum, represents a transcriptional repressor binding site. Purified recombinant AdhA displayed the highest substrate specificities towards ethanol and n-propanol and their corresponding aldehydes.
谷氨酸棒杆菌R的adhA基因编码一种同二聚体、依赖NAD的345个氨基酸残基的醇脱氢酶，每个亚基含有两个锌离子。adhA基因的染色体失活使该菌株无法以乙醇或正丙醇作为唯一碳源生长。RNA杂交分析表明，adhA转录不仅由这两种底物诱导，而且还受到葡萄糖分解代谢物阻遏作用的影响。因此，只有在葡萄糖耗尽后才检测到AdhA活性的诱导和乙醇利用。adhA启动子区域中潜在的环磷酸腺苷（cAMP）受体结合位点和序列5'-GCAATTGATG-N(8)-CACAATTGC-3'的反向重复序列中的一个或两个缺失强烈表明，IR（与谷氨酸棒杆菌的其他调控DNA元件没有显著相似性）代表一个转录阻遏物结合位点。纯化的重组AdhA对乙醇和正丙醇及其相应的醛表现出最高的底物特异性。
