Iwai A, Ito H, Mizuno T, Mori H, Matsui H, Honma M, Okada G, Chiba S
Department of Bioscience and Chemistry, Hokkaido University, Sapporo, Japan.
J Bacteriol. 1994 Dec;176(24):7730-4. doi: 10.1128/jb.176.24.7730-7734.1994.
The gene encoding an extracellular isomalto-dextranase, designated imd, was isolated from the chromosomal DNA of Arthrobacter globiformis T6 and cloned and expressed in Escherichia coli. A single open reading frame consisting of 1,926 base pairs that encoded a polypeptide composed of a signal peptide of 39 amino acids and a mature protein of 602 amino acids (M(r), 65,900) was found. The primary structure had no significant homology with the structures of any other reported carbohydrases, including two other dextranases. Transformed E. coli cells carrying the 2.3-kb fragment overproduced isomalto-dextranase into the periplasmic space under control of the promoter of the imd gene itself.
从球形节杆菌T6的染色体DNA中分离出编码胞外异麦芽糖 - 葡聚糖酶（命名为imd）的基因，并在大肠杆菌中进行克隆和表达。发现了一个由1926个碱基对组成的单一开放阅读框，其编码一种多肽，该多肽由39个氨基酸的信号肽和602个氨基酸（M(r)，65,900）的成熟蛋白组成。其一级结构与任何其他已报道的碳水化合物酶的结构均无明显同源性，包括另外两种葡聚糖酶。携带2.3kb片段的转化大肠杆菌细胞在imd基因自身启动子的控制下，将异麦芽糖 - 葡聚糖酶过量产生到周质空间中。
