TY - JOUR
T1 - Expression and characterization of the chitin-binding domain of chitinase A1 from Bacillus circulans WL-12
AU - Hashimoto, Masayuki
AU - Ikegami, Takahisa
AU - Seino, Shizuka
AU - Ohuchi, Nobuhumi
AU - Fukada, Harumi
AU - Sugiyama, Junji
AU - Shirakawa, Masahiro
AU - Watanabe, Takeshi
PY - 2000/6
Y1 - 2000/6
N2 - Chitinase A1 from Bacillus circulans WL-12 comprises an N-terminal catalytic domain, two fibronectin type III-like domains, and a C-terminal chitin-binding domain (ChBB). In order to study the biochemical properties and structure of the ChBD, ChBD(ChiA1) was produced in Escherichia coli using a pET expression system and purified by chitin affinity column chromatography. Purified ChBD(ChiA1) specifically bound to various forms of insoluble chitin but not to other polysaccharides, including chitosan, cellulose, and starch. Interaction of soluble chitinous substrates with ChBD(ChiA1) was not detected by means of nuclear magnetic resonance and isothermal titration calorimetry. In addition, the presence of soluble substrates did not interfere with the binding of ChBD(ChiA1) to regenerated chitin. These observations suggest that ChBD(ChiA1) recognizes a structure which is present in insoluble or crystalline chitin but not in chito- oligosaccharides or in soluble derivatives of chitin. ChBD(ChiA1) exhibited binding activity over a wide range of pHs, and the binding activity was enhanced at pHs near its pI and by the presence of NaCl, suggesting that the binding of ChBD(ChiA1) is mediated mainly by hydrophobic interactions. Hydrolysis of β-chitin microcrystals by intact chitinase A1 and by a deletion derivative lacking the ChBD suggested that the ChBD is not absolutely required for hydrolysis of β-chitin microcrystals but greatly enhances the efficiency of degradation.
AB - Chitinase A1 from Bacillus circulans WL-12 comprises an N-terminal catalytic domain, two fibronectin type III-like domains, and a C-terminal chitin-binding domain (ChBB). In order to study the biochemical properties and structure of the ChBD, ChBD(ChiA1) was produced in Escherichia coli using a pET expression system and purified by chitin affinity column chromatography. Purified ChBD(ChiA1) specifically bound to various forms of insoluble chitin but not to other polysaccharides, including chitosan, cellulose, and starch. Interaction of soluble chitinous substrates with ChBD(ChiA1) was not detected by means of nuclear magnetic resonance and isothermal titration calorimetry. In addition, the presence of soluble substrates did not interfere with the binding of ChBD(ChiA1) to regenerated chitin. These observations suggest that ChBD(ChiA1) recognizes a structure which is present in insoluble or crystalline chitin but not in chito- oligosaccharides or in soluble derivatives of chitin. ChBD(ChiA1) exhibited binding activity over a wide range of pHs, and the binding activity was enhanced at pHs near its pI and by the presence of NaCl, suggesting that the binding of ChBD(ChiA1) is mediated mainly by hydrophobic interactions. Hydrolysis of β-chitin microcrystals by intact chitinase A1 and by a deletion derivative lacking the ChBD suggested that the ChBD is not absolutely required for hydrolysis of β-chitin microcrystals but greatly enhances the efficiency of degradation.
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U2 - 10.1128/JB.182.11.3045-3054.2000
DO - 10.1128/JB.182.11.3045-3054.2000
M3 - Article
C2 - 10809681
AN - SCOPUS:0034127684
SN - 0021-9193
VL - 182
SP - 3045
EP - 3054
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 11
ER -