1. Heterogonous expression and characterization of a plant class IV chitinase from the pitcher of the carnivorous plant Nepenthes alata
- Author
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Tatsuro Hamada, Naoya Hatano, Kana Ishisaki, Yuji Honda, and Hajime Taniguchi
- Subjects
Recombinant Fusion Proteins ,Molecular Sequence Data ,Gene Expression ,Oligosaccharides ,Caryophyllaceae ,Biology ,Biochemistry ,Chromatography, Affinity ,Protein Structure, Secondary ,Acetylglucosamine ,Hydrolysis ,Catalytic Domain ,Glycoside hydrolase ,Amino Acid Sequence ,Cloning, Molecular ,Chromatography, High Pressure Liquid ,Plant Proteins ,chemistry.chemical_classification ,Sequence Homology, Amino Acid ,Chitinases ,Glycosidic bond ,Hydrogen-Ion Concentration ,Oligosaccharide ,biology.organism_classification ,Nepenthes alata ,Amino acid ,Kinetics ,Enzyme ,chemistry ,Chitinase ,biology.protein - Abstract
A class IV chitinase belonging to the glycoside hydrolase 19 family from Nepenthes alata (NaCHIT1) was expressed in Escherichia coli. The enzyme exhibited weak activity toward polymeric substrates and significant activity toward (GlcNAc)(n) [β-1,4-linked oligosaccharide of GlcNAc with a polymerization degree of n (n = 4-6)]. The enzyme hydrolyzed the third and fourth glycosidic linkages from the non-reducing end of (GlcNAc)(6). The pH optimum of the enzymatic reaction was 5.5 at 37°C. The optimal temperature for activity was 60°C in 50 mM sodium acetate buffer (pH 5.5). The anomeric form of the products indicated that it was an inverting enzyme. The k(cat)/K(m) of the (GlcNAc)(n) hydrolysis increased with an increase in the degree of polymerization. Amino acid sequence alignment analysis between NaCHIT1 and a class IV chitinase from a Picea abies (Norway spruce) suggested that the deletion of four loops likely led the enzyme to optimize the (GlcNAc)(n) hydrolytic reaction rather than the hydrolysis of polymeric substrates.
- Published
- 2011