A highly Conserved Aspartic Acid Residue of the Chitosanase from Bacillus Sp. TS Is Involved in the Substrate Binding.
The chitosanase from Bacillus sp. TS (CsnTS) is an enzyme belonging to the glycoside hydrolase family 8. The sequence of CsnTS shares 98 % identity with the chitosanase from Bacillus sp. K17. Crystallography analysis and site-direct mutagenesis of the chitosanase from Bacillus sp. K17 identified the important residues involved in the catalytic interaction and substrate binding. However, despite progress in understanding the catalytic mechanism of the chitosanase from the family GH8, the functional roles of some residues that are highly conserved throughout this family have not been fully elucidated. This study focused on one of these residues, i.e., the aspartic acid residue at position 318. We found that apart from asparagine, mutation of Asp318 resulted in significant loss of enzyme activity. In-depth investigations showed that mutation of this residue not only impaired enzymatic activity but also affected substrate binding. Taken together, our results showed that Asp318 plays an important role in CsnTS activity.
National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Zhanping
Z
Zhou
Institute of Agro-food Science and Technology, Shandong Academy of Agricultural Sciences, Jinan, China.
Shuangzhi
S
Zhao
National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Yang
Y
Liu
National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Zhengying
Z
Chang
National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Yanhe
Y
Ma
Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Vic, Parkville, 3052, Australia.
Jian
J
Li
National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China. Jiangning.Song@monash.edu.|Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, 3800, Australia. Jiangning.Song@monash.edu.|Monash Centre for Data Science, Faculty of Information Technology, Monash University, Melbourne, VIC, 3800, Australia. Jiangning.Song@monash.edu.
Jiangning
J
Song
D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology*; D017124:Conserved Sequence; D006026:Glycoside Hydrolases / Q000737:chemistry*; D007700:Kinetics; D050505:Mutant Proteins / Q000302:isolation & purification; D009154:Mutation / Q000235:genetics; D011487:Protein Conformation; D058767:Protein Unfolding; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013696:Temperature
D050505:Mutant Proteins; D001224:Aspartic Acid; D006026:Glycoside Hydrolases; C019868:chitosanase
Aspartic acid; Chitosanase; Enzyme-substrate interaction; Glycoside hydrolase family 8