3W6C: Crystal structure of catalytic domain of chitinase from Ralstonia sp. A-471 in complex with disaccharide

Citation:
Abstract
Chitinase C from Ralstonia sp. A-471 (Ra-ChiC) has a catalytic domain sequence similar to goose-type (G-type) lysozymes and, unlike other chitinases, belongs to glycohydrolase (GH) family 23. Using NMR spectroscopy, however, Ra-ChiC was found to interact only with the chitin dimer but not with the peptidoglycan fragment. Here we report the crystal structures of wild-type, E141Q, and E162Q of the catalytic domain of Ra-ChiC with or without chitin oligosaccharides. Ra-ChiC has a substrate-binding site including a tunnel-shaped cavity, which determines the substrate specificity. Mutation analyses based on this structural information indicated that a highly conserved Glu-141 acts as a catalytic acid, and that Asp-226 located at the roof of the tunnel activates a water molecule as a catalytic base. The unique arrangement of the catalytic residues makes a clear contrast to the other GH23 members and also to inverting GH19 chitinases.
PDB ID: 3W6CDownload
MMDB ID: 110019
PDB Deposition Date: 2013/2/14
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 3W6C: monomeric; determined by author
Molecular Components in 3W6C
Label Count Molecule
Protein (1 molecule)
1
Lysozyme-like Chitinolytic Enzyme
Molecule annotation
Chemicals (5 molecules)
1
5
* Click molecule labels to explore molecular sequence information.

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