Stereochemical course of the hydrolysis reaction catalyzed by chitinases A1 and D from Bacillus circulans WL-12.
Chitinases A1 and D were purified from the periplasmic proteins produced by Escherichia coli HB101 harbouring recombinant plasmids carrying respectively the chiA and chiD genes of Bacillus circulans WL-12. HPLC analysis indicated that during the hydrolysis of chitotriose, both chitinases initially produce N-acetylglucosamine and only one anomer of chitobiose. 1H NMR spectroscopy of the hydrolysis of chitotetraitol showed that this anomer corresponds to beta-chitobiose, demonstrating that chitinases A1 and D act by a molecular mechanism that retains the anomeric configuration. This mechanism is similar to that of lysozymes although both chitinases belong to a family of proteins sharing no demonstrable amino acid sequence similarity with lysozymes.
Armand
S
S
Centre de Recherches sur les Macromolécules Végétales, CNRS, Grenoble, France.
Tomita
H
H
Heyraud
A
A
Gey
C
C
Watanabe
T
T
Henrissat
B
B
D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D002384:Catalysis; D002688:Chitinases / Q000302:isolation & purification / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D013379:Substrate Specificity
D007527:Isoenzymes; D002688:Chitinases