2CWR

Crystal structure of chitin biding domain of chitinase from Pyrococcus furiosus

Summary for 2CWR

• Entry DOI: 10.2210/pdb2cwr/pdb
• Descriptor: chitinase (2 entities in total)
• Functional Keywords: chitinase, chitin-binding domain, pyrococcus furiosus, endoglucanase, chitin, hyperthermophilic, hydrolase
• Biological source: Pyrococcus furiosus
• Total number of polymer chains: 1
• Total formula weight: 10964.10

Authors

Uegaki, K.,Nakamura, T.,Ishikawa, K.,Matsumura, H. (deposition date: 2005-06-24, release date: 2006-07-11, Last modification date: 2024-03-13)

Primary citation

Nakamura, T.,Mine, S.,Hagihara, Y.,Ishikawa, K.,Ikegami, T.,Uegaki, K.
Tertiary structure and carbohydrate recognition by the chitin-binding domain of a hyperthermophilic chitinase from Pyrococcus furiosus.
J.Mol.Biol., 381:670-680, 2008

PubMed Abstract: A chitinase is a hyperthermophilic glycosidase that effectively hydrolyzes both alpha and beta crystalline chitins; that studied here was engineered from the genes PF1233 and PF1234 of Pyrococcus furiosus. This chitinase has unique structural features and contains two catalytic domains (AD1 and AD2) and two chitin-binding domains (ChBDs; ChBD1 and ChBD2). A partial enzyme carrying AD2 and ChBD2 also effectively hydrolyzes crystalline chitin. We determined the NMR and crystal structures of ChBD2, which significantly enhances the activity of the catalytic domain. There was no significant difference between the NMR and crystal structures. The overall structure of ChBD2, which consists of two four-stranded beta-sheets, was composed of a typical beta-sandwich architecture and was similar to that of other carbohydrate-binding module 2 family proteins, despite low sequence similarity. The chitin-binding surface identified by NMR was flat and contained a strip of three solvent-exposed Trp residues (Trp274, Trp308 and Trp326) flanked by acidic residues (Glu279 and Asp281). These acidic residues form a negatively charged patch and are a characteristic feature of ChBD2. Mutagenesis analysis indicated that hydrophobic interaction was dominant for the recognition of crystalline chitin and that the acidic residues were responsible for a higher substrate specificity of ChBD2 for chitin compared with that of cellulose. These results provide the first structure of a hyperthermostable ChBD and yield new insight into the mechanism of protein-carbohydrate recognition. This is important in the development of technology for the exploitation of biomass.

PubMed: 18582475
DOI: 10.1016/j.jmb.2008.06.006

Experimental method

X-RAY DIFFRACTION (1.7 Å)