Chitin, a polymer of N-acetyl-d-glucosamine (GlcNAc), can be degraded by chitinase, which is produced by higher plants, vertebrates, and bacteria. Chitinases are characterized by the ability to hydrolyze the beta-1,4-linkages in the chitin chain by either an endolytic or an exolytic mechanism. Chitinase 1198 is a novel endochitinase from the genome sequence of Chitinibacter tainanensis CT01. Herein, we report the findings of molecular simulations and bioassays for chitinase 1198. Our experimental results suggest that chitinase 1198 can recognize the nonreducing end of chitin and cleave the second or third glycosidic linkage from the nonreducing end of chitin oligomers. Furthermore, our simulations results revealed that chitinase 1198 is more likely to bind chitin oligomers with the main hydrogen bonds of the Asp440, the second GlcNAc unit of chitin oligomers, and degrade chitin oligomers to (GlcNAc)2 molecules. Moreover, chitinase 1198 is less likely to bind chitin oligomers with the main hydrogen bonds of the Asp440, the third GlcNAc unit of chitin oligomers, and degrade chitin oligomers to (GlcNAc)3 molecules. Lastly, chitinase 1198 can bind (GlcNAc)3 molecules with the main hydrogen bonds of the Asp440, the second GlcNAc of the (GlcNAc)3 molecules, and degrade chitin oligomers to GlcNAc and (GlcNAc)2 molecules.
Keywords: bioassay; chitinase; gene cloning; molecular simulations.