Nitschke L, Heeger K, Bender H, Schulz G E
Institut für Organische Chemie und Biochemie, Freiburg, Federal Republic of Germany.
Appl Microbiol Biotechnol. 1990 Aug;33(5):542-6. doi: 10.1007/BF00172548.
The beta-cyclodextrin glycosyltransferase (beta-CGTase) gene was isolated from a lambda-library prepared from Bacillus circulans strain no. 8. It was subcloned into plasmid pTZ and expressed by its endogenous regulatory sequences in Escherichia coli JM 103. The structural gene was sequenced and showed an open reading frame for a polypeptide of 718 amino acid residues. The recombinant beta-CGTase had the same enzymatic properties as the extracellular CGTase (684 amino acid residues, corresponding to a mol. wt. of 74416) produced by B. circulans strain no. 8. The amino acid sequence showed the highest homology (74.6% identical amino acids) with the CGTase of B. circulans strain F-2, which had been erroneously described as an amylase. The homology with the enzyme from the alkalophilic Bacillus sp. strain no. 1011 was 71.4%. The amino acid sequence derived will be used for elucidating the three-dimensional structure of the enzyme.
β-环糊精糖基转移酶（β-CGTase）基因是从环状芽孢杆菌8号菌株制备的λ文库中分离出来的。它被亚克隆到质粒pTZ中，并通过其内源调控序列在大肠杆菌JM 103中表达。对该结构基因进行了测序，结果显示其开放阅读框编码一个由718个氨基酸残基组成的多肽。重组β-CGTase具有与环状芽孢杆菌8号菌株产生的细胞外CGTase（684个氨基酸残基，对应分子量为74416）相同的酶学性质。氨基酸序列与环状芽孢杆菌F-2菌株的CGTase显示出最高的同源性（74.6%的相同氨基酸），该菌株的CGTase曾被错误地描述为淀粉酶。与嗜碱芽孢杆菌1011号菌株的酶的同源性为71.4%。推导得到的氨基酸序列将用于阐明该酶的三维结构。
