Modulation of the transglycosylation activity of plant family GH18 chitinase by removing or introducing a tryptophan side chain
| Autor: | Tomoyuki Numata, Takuo Osawa, Tamo Fukamizo, Naoyuki Umemoto, Takayuki Ohnuma |
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| Rok vydání: | 2015 |
| Předmět: |
Cycas
Models Molecular Glycosylation Transglycosylation Biophysics Chitin Crystal structure Crystallography X-Ray medicine.disease_cause Biochemistry Chitin oligosaccharide Cycas revoluta Structural Biology Catalytic Domain Genetics medicine Side chain Molecular Biology Alanine Mutation biology Chemistry Chitinases Tryptophan Chitinase Cell Biology Tryptophan residue biology.organism_classification Matrix-assisted laser desorption/ionization Mutagenesis Site-Directed biology.protein |
| Zdroj: | FEBS Letters. 589:2327-2333 |
| ISSN: | 0014-5793 |
| DOI: | 10.1016/j.febslet.2015.07.018 |
| Popis: | Transglycosylation (TG) activity of a family GH18 chitinase from the cycad, Cycas revoluta, (CrChiA) was modulated by removing or introducing a tryptophan side chain. The removal from subsite +3 through mutation of Trp168 to alanine suppressed TG activity, while introduction into subsite +1 through mutation of Gly77 to tryptophan (CrChiA-G77W) enhanced TG activity. The crystal structures of an inactive double mutant of CrChiA (CrChiA-G77W/E119Q) with one or two N-acetylglucosamine residues occupying subsites +1 or +1/+2, respectively, revealed that the Trp77 side chain was oriented toward +1 GlcNAc to be stacked with it face-to-face, but rotated away from subsite +1 in the absence of GlcNAc at the subsite. Aromatic residues in the aglycon-binding site are key determinants of TG activity of GH18 chitinases. |
| Databáze: | OpenAIRE |
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