摘要
巨大芽孢杆菌（Ｂａｃｉｌｕｓｍｅｇａｔｅｒｉｕｍ）ＡＳ１．１２７的淀粉酶基因的全碱基序列已被测定。结构基因由１９８２ｂｐ的单一开读框架组成。由ＤＮＡ序列推测出的前体酶蛋白由６５９个氨基酸组成，Ｎ端３３个氨基酸为信号肽。成熟酶分子由６２６个氨基酸组成，分子量为６８６７６ｋＤ。该淀粉酶属糖化型α淀粉酶。并与枯草杆菌（Ｂ．ｓｕｂｔｉｌｉｓ）１６８产生的糖化型α淀粉酶之间有８３３％的同源性。分析发现两种菌产生的酶分子的Ｎ端３／４的同源性为９０４％，而Ｃ端１／４的同源性只有７０％。序列排比结果说明在淀粉酶基因的趋异进化过程中，基因突变和遗传重组都曾起过作用。
The nucleotide sequence of α amylase gene from Bacillus megaterium AS1.127 has been determined. The structural gene is composed of 1982 bp. Proamylase deduced from nucleotide sequence is composed of 659 amino acids. 33 amino acids at N terminal was deduced as signal peptide. The mature α amylase is composed of 626 amino acids. The molecular weight is 68 676kD. It belongs to saccharifying α amylase with 83.8% homogeneity with Bacillus subtitis 168. We find that the different parts of these two amylases possess different homogeneity ratio:the first 3/4 from N terminal end the homogeneity is 90.4%; the 1/4 from C terminal end only 70%. Comparison of two DNA sequences suggested that both gene mutation and genetic recombination were involved in the divergent evolution process.
出处
《生物工程学报》
CAS
CSCD
北大核心
1999年第1期68-74,共7页
Chinese Journal of Biotechnology
基金
国家高技术研究发展计划
