Functions of the COOH-terminal region of cyclodextrin glucanotransferase of alkalophilic Bacillus sp. #1011: relation to catalyzing activity and pH stability.
Cyclodextrin glucanotransferase (beta-CGTase) of alkalophilic Bacillus sp. #1011 degrades starch to mainly beta-cyclodextrin (beta-CD). This enzyme is considered to contain an extra-polypeptide in its COOH-terminal region in addition to its NH2-terminal domain which exhibits the starch-degrading activity. To analyze the functions of this extra-polypeptide in the beta-CGTase, two mutated enzymes, in which DNA regions encoding 10 or 13 amino acids from the COOH-terminus were deleted, were obtained. The mutated enzymes degraded starch to glucose, maltooligosaccharides and alpha-CD, in addition to beta-CD. Furthermore, the pH stability of the mutated enzymes in the alkaline pH range (pH 9-11) was reduced.
Kimura
K
K
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Kataoka
S
S
Nakamura
A
A
Takano
T
T
Kobayashi
S
S
Yamane
K
K
D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010957:Plasmids
D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase