Structure of a Two-Domain Chitotriosidase from Serratia Marcescens at 1.9 Angstrom Resoltuion
Van Aalten, D.M.F., Synstad, B., Brurberg, M.B., Hough, E., Riise, B.W., Eijsink, V.G.H., Wierenga, R.K.(2000) Proc Natl Acad Sci U S A 97: 5842
- PubMed: 10823940 
- DOI: https://doi.org/10.1073/pnas.97.11.5842
- Primary Citation of Related Structures:  
1E15 - PubMed Abstract: 
In this paper, we describe the structure of chitinase B from Serratia marcescens, which consists of a catalytic domain with a TIM-barrel fold and a 49-residue C-terminal chitin-binding domain. This chitinase is the first structure of a bacterial exochitinase, and it represents one of only a few examples of a glycosyl hydrolase structure having interacting catalytic and substrate-binding domains. The chitin-binding domain has exposed aromatic residues that contribute to a 55-A long continuous aromatic stretch extending into the active site. Binding of chitin oligomers is blocked beyond the -3 subsite, which explains why the enzyme has chitotriosidase activity and degrades the chitin chain from the nonreducing end. Comparison of the chitinase B structure with that of chitinase A explains why these enzymes act synergistically in the degradation of chitin.
Organizational Affiliation: 
Biocenter Oulu, Department of Biochemistry, University of Oulu, Linnanmaa, FIN-90570 Oulu, Finland. dava@davapc1.bioch.dundee.ac.uk