Title: Purification, characterization and cloning of a chitinase from Bacillus sp NCTU2
Authors: Wen, CM
Tseng, CS
Cheng, CY
Li, YK
Department of Applied Chemistry
Keywords: Bacillus cereus;chitin;chito-oligosaccharide
Issue Date: 1-Jun-2002
Abstract: A chitin-degrading Bacillus strain, designated as NCTU2, was screened from soil and identified. An extracellular chitinase was purified to > 90% homogeneity from the culture filtrate. The purification involved hydrophobic-interaction and gel-filtration chromatographic separations with a yield of 58%. The purified enzyme (ChiNCTU2) is a monomeric protein with an estimated molecular mass of 36.5 kDa and a pI of 6.3. It is thermally stable at 60 degreesC and pH 6-8 for more than 3 h. The optimal activity is in the range of 50-60 degreesC at pH 7.0. Chitobiose is the predominant product throughout the enzymic hydrolysis of the colloidal chitin, indicating that the purified chitinase is an exo-chitinase. Chito-oligosaccharides [with degree of polymerization (DP) values of 4-6] are good substrates of the purified enzyme, whereas a DP3 oligomer was slowly hydrolysed to form DP1 and DP2 sugars. The first 15 N-terminal amino acids of the enzyme were determined to be ANNLGSKLLVGYWHN, which is highly homologous to that of ChiA from Bacillus cereus. A PCR cloning technique was employed to obtain the corresponding gene from Bacillus NCTU2. The gene sequence was determined to be 1080 bp, encoding a polypeptide of 360 amino acids with the first 27 amino acids as the signal peptide.
URI: http://dx.doi.org/10.1042/0885-4513:0350213
ISSN: 0885-4513
DOI: 10.1042/0885-4513:0350213
Volume: 35
Begin Page: 213
End Page: 219
Appears in Collections:Articles