title: Purification, characterization, and gene cloning of a chitosanase from Bacillus species strain s65.
abstract: For the production of oligosaccharides from chitosan, a chitosanase-producing bacterium, S65, was isolated from soil. On the basis of phylogenetic analysis of the 16S rDNA gene sequence and phenotypic analysis, S65 was identified as a Bacillus sp. strain. This bacterium constitutively produced chitosanase in a culture medium without chitosan as an inducer. S65 chitosanase was homogeneously purified by DEAE Sepharose fast flow anion exchange followed by Superdex 75 size exclusion, and the molecular weight was 45 kDa according to SDS-PAGE. Enzyme analysis showed that the optimum pH and temperature of S65 were 6.0 and 65 degrees C, respectively. Catalytic activity was stable from pH 5.5-6.5 at temperatures below 40 degrees C, and the pI of chitosanase was about 6.0 as determined by a test tube method. S65 chitosanase degraded carboxymethyl cellulose (CMC) at the degree of about 5.3% relative to the value of soluble chitosan, but it cannot hydrolyze colloidal chitin and crystalline cellulose. Gene encoding was cloned and sequenced. The deduced amino acid sequence of the S65 exhibited the highest homology to those of family 8 glycanase, suggesting that the enzyme belonged to family 8.
authors.affiliation: Ion Beam Bioengineering Key Lab, Institute of Plasma Physics, Chinese Academy of Sciences, 230031, Hefei 1126#, People's Republic of China.
authors.forename: Caixin
authors.initials: C
authors.lastname: Su
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.forename: Liming
authors.initials: L
authors.lastname: Yao
authors.forename: Zengliang
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D002384:Catalysis; D018797:Cell Cycle Proteins; D003001:Cloning, Molecular; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008670:Metals / Q000494:pharmacology; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D012988:Soil Microbiology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: C089931:CDC36 protein, S cerevisiae; D018797:Cell Cycle Proteins; D008670:Metals; D012336:RNA, Ribosomal, 16S; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D006026:Glycoside Hydrolases; C019868:chitosanase