Cloning, expression, and characterization of a chitinase from the chitinolytic bacterium Aeromonas hydrophila strain SUWA-9.
The chitinolytic bacterium Aeromonas hydrophila strain SUWA-9, which was isolated from freshwater in Lake Suwa (Nagano Prefecture, Japan), produced several kinds of chitin-degrading enzymes. A gene coding for an endo-type chitinase (chiA) was isolated from SUWA-9. The chiA ORF encodes a polypeptide of 865 amino acid residues with a molecular mass of 91.6 kDa. The deduced amino acid sequence showed high similarity to those of bacterial chitinases classified into family 18 of glycosyl hydrolases. chiA was expressed in Escherichia coli and the recombinant chitinase (ChiA) was purified and examined. The enzyme hydrolyzed N-acetylchitooligomers from trimer to pentamer and produced monomer and dimer as a final product. It also reacted toward colloidal chitin and chitosan with a low degree of deacetylation. When cells of SUWA-9 were grown in the presence of colloidal chitin, a 60 kDa-truncated form of ChiA that had lost the C-terminal chitin-binding domain was secreted.
Lan
Xiqian
X
Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Japan.
Zhang
Xin
X
Hu
Junhua
J
Shimosaka
Makoto
M
D000107:Acetylation; D016980:Aeromonas hydrophila / Q000201:enzymology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D006868:Hydrolysis; D009844:Oligosaccharides / Q000378:metabolism; D016366:Open Reading Frames
D001426:Bacterial Proteins; D009844:Oligosaccharides; D002686:Chitin; D002688:Chitinases