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Directional degradation of β‐chitin by chitinase A1 revealed by a novel reducing end labelling technique
Author(s) -
Imai Tomoya,
Watanabe Takeshi,
Yui Toshifumi,
Sugiyama Junji
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)03249-5
Subject(s) - chitin , chitinase , labelling , bacillus circulans , chemistry , streptavidin , biotin , biochemistry , chitosan , enzyme
A novel procedure for labelling the molecular ends of β‐chitin crystals has been established. By introducing a hydrazide derivative of biotin at the reducing end of a chitin chain, followed by a specific interaction between biotin and streptavidin coupled with a colloidal gold particle, the chain directionality of β‐chitin microcrystals could be directly visualized by transmission electron microscopy. This method allowed to certify the parallelism of the chitin chains in the β‐chitin microcrystals, and also to label the reducing tips of β‐chitin microcrystals degraded by Bacillus circulans chitinase A1. With these substrates, the labelling occurred only at their tapered tip, which indicates that the digestion of these crystals proceeded from their reducing end. The generalization of this new labelling method to other polysaccharide crystals is discussed.