Identification of a novel cyclomaltodextrinase annotated as a neopullulanase in the genome of Bacillus cereus

• Published in: Archives of microbiology Vol. 205; no. 3; p. 86
• Main Authors: Park, Bo-Ram, MubarakAli, Davoodbasha, Kim, Jung-Wan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2023; Springer Nature B.V
• Subjects: Amino Acid Sequence; Amino acids; Amylolytic enzymes; Bacillus cereus; Bacillus cereus - genetics; Bacillus cereus - metabolism; Biochemistry; Biomedical and Life Sciences; Biotechnology; Carbon dioxide; Cations; Cell Biology; Cobalt; Copper; Cyclomaltodextrinase; Diarrhea; Ecology; Enzymatic activity; Enzyme activity; Enzymes; Foodborne diseases; Foodborne pathogens; Genomes; Glycogen; Glycogens; Glycoside Hydrolases - metabolism; Ingestion; Life Sciences; Maltodextrin; Maltose; Maltose - metabolism; Maltotriose; Microbial Ecology; Microbiology; Neopullulanase; Opportunist infection; Original Paper; Pathogens; Soil bacteria; Soil microorganisms; Substrate preferences; Substrate Specificity; Substrates; Sugar; Vomiting; Transglycosylation; Cyclomaltodextrinase; Neopullulanase; α-amylase family GH13; Bacillus cereus
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-022-03390-y

Bacillus cereus
is a rod-shaped, gram-positive, motile, and β-hemolytic soil bacterium.
B. cereus
is an opportunistic pathogen, often responsible for human foodborne illness that is caused by ingestion of starchy foods with symptoms of diarrhea and vomiting. Among the numerous amylolytic enzymes in the genome of the pathogen, the one annotated as a putative neopullulanase (NPase) was cloned and its biochemical properties were characterized in this study. The corresponding gene encoded an enzyme of 586 amino acids with a predicted molecular mass of 68.25 kDa. The putative NPase shared 43.7–59.2% of identity with NPases, cyclomaltodextrinases (CDases), and maltogenic amylases from various bacteria, but shared very low similarity with other amylolytic enzymes of
B. cereus
. The optimal pH and temperature of the enzyme was 6.5 and 37 ℃, respectively. The enzyme activity was decreased by the cations tested in this study and completely inhibited by Co
2+
and Cu
2+
. The purified enzyme showed substrate preference in the order of α-CD > β-CD > starch > maltodextrin > γ-CD and hydrolyzed them mainly to maltose. However, it did not hydrolyze maltose, pullulan, and glycogen. The enzyme was designated herein as a CDase of
B. cereus
(BcCDase). Furthermore, the enzyme could transfer the sugars released from CDs and maltotriose to acceptor molecules. BcCDase was likely to be involved in the maltodextrin metabolism in
B. cereus
.