Yabutani T, Maehara A, Ueda S, Yamane T
Department of Applied Biological Sciences, Faculty of Agriculture, Nagoya University, Japan.
FEMS Microbiol Lett. 1995 Nov 1;133(1-2):85-90. doi: 10.1111/j.1574-6968.1995.tb07865.x.
The beta-ketothiolase gene (phaA) and acetoacetyl-CoA reductase gene (phaB) were isolated from Paracoccus denitrificans. Nucleotide sequence analysis showed that they encoded proteins of 391 amino acids with a molecular mass of 40,744 Da and of 242 amino acids with a molecular mass of 25,614 Da, respectively. The predicted gene products exhibited high amino acid identities with those from other bacteria: 64.4-74.0% for the phaA gene product and 47.6-80.6% for the phaB gene product, respectively. Both genes were co-transcribed in a recombinant Escherichia coli. In addition, promoter activity was detected upstream of the phaA gene. Hence, the two genes are organized as an operon, phaA-phaB, in P. denitrificans. NADH was preferred to NADPH as a cofactor of acetoacetyl-CoA reductase.
从反硝化副球菌中分离出β-酮硫解酶基因（phaA）和乙酰乙酰辅酶A还原酶基因（phaB）。核苷酸序列分析表明，它们分别编码由391个氨基酸组成、分子量为40744 Da的蛋白质和由242个氨基酸组成、分子量为25614 Da的蛋白质。预测的基因产物与其他细菌的相应产物具有较高的氨基酸同一性：phaA基因产物的氨基酸同一性为64.4%-74.0%，phaB基因产物的氨基酸同一性为47.6%-80.6%。这两个基因在重组大肠杆菌中共同转录。此外，在phaA基因上游检测到启动子活性。因此，在反硝化副球菌中，这两个基因组成一个操纵子phaA-phaB。作为乙酰乙酰辅酶A还原酶的辅因子，NADH比NADPH更受青睐。
