research papers
The four-domain structure of chitinase 60 from Moritella marina (MmChi60) is outstanding in its complexity. Many glycoside hydrolases, such as chitinases and cellulases, have multi-domain structures, but only a few have been solved. The flexibility of the hinge regions between the domains apparently makes these proteins difficult to crystallize. The analysis of an active-site mutant of MmChi60 in an unliganded form and in complex with the substrates NAG4 and NAG5 revealed significant differences in the substrate-binding site compared with the previously determined complexes of most studied chitinases. A SAXS experiment demonstrated that in addition to the elongated state found in the crystal, the protein can adapt other conformations in solution ranging from fully extended to compact.
Keywords: chitinase; psychrophilic; ligand binding; multi-domain; chitin; chitin-binding domain; Ig-like domain; TIM β/α-barrel; flexibility; hinge regions; SAXS.
Supporting information
Portable Document Format (PDF) file https://doi.org/10.1107/S1399004713032264/dz5316sup1.pdf |
PDB references: chitinase, E153Q mutant, 4mb3; complex with NAG4, 4mb4; complex with NAG5, 4mb5