BBB : Vol. 64 (2000) , No. 7 pp.1379-1393

The Primary Structure of the Subunit in Bacillus thermoamyloliquefaciens KP1071 Molecular Weight 540,000 Homohexameric α-Glucosidase II Belonging to the Glycosyl Hydrolase Family 31

Shin-ichi KASHIWABARA¹⁾, Sayuri AZUMA¹⁾, Masao TSUDUKI¹⁾ and Yuzuru SUZUKI¹⁾

1) Laboratory of Microbial Physiology and Applied Microbiology, Department of Applied Biochemistry, Kyoto Prefectural University

(Received December 15, 1999)
(Accepted March 6, 2000)

The gene that coded for the subunit of an molecular weight (M_r) 540,000 homohexameric α-glucosidase II (α-D-glucoside glucohydrolase, EC 3.2.1.20) produced by Bacillus thermoamyloliquefaciens KP1071 (FERM-P8477) growing at 30 to 66°C was expressed in Escherichia coli HB101. The resulting homohexameric enzyme had a half-life of 10 min at 80°C. Its purification and characterization showed that the enzyme was identical with the native one except for the latter deleting 7 N-terminal residues found in the former. The primary sequence of the subunit with 787 residues and an M_r of 91,070 deduced from the gene was 24-34% identical to the corresponding sequences of 15 α-glucosidases in the glycosyl hydrolase family 31 from 14 eukaryotic origins and the archaeon Sulfolobus solfataricus 98/2.
From the sequence analysis by the neural network method of Rost and Sander [Rost, B. and Sander, C., Proteins: Struct. Funct. Genet., 19, 55-72 (1994)], we inferred that α-glucosidase II might make each subunit of 3 secondary structural regions, i.e., one N-terminal β region, one central α/β region with two catalytic residues Asp407 and Asp484, and one C-terminal β region.

Key words:

thermostable homohexameric α-glucosidase; gene cloning; Bacillus thermoamyloliquefaciens; glycosyl hydrolase family 31; multiple sequence alignments

	To cite this article:
	Shin-ichi KASHIWABARA, Sayuri AZUMA, Masao TSUDUKI and Yuzuru SUZUKI, “The Primary Structure of the Subunit in Bacillus thermoamyloliquefaciens KP1071 Molecular Weight 540,000 Homohexameric α-Glucosidase II Belonging to the Glycosyl Hydrolase Family 31”, Biosci. Biotechnol. Biochem., Vol. 64, 1379-1393 (2000) .

	doi:10.1271/bbb.64.1379
	JOI JST.JSTAGE/bbb/64.1379