The Active Site Topology of Aspergillus nigerEndopolygalacturonase II as Studied by Site-directed Mutagenesis
نویسندگان
چکیده
منابع مشابه
The active site topology of Aspergillus niger endopolygalacturonase II as studied by site-directed mutagenesis.
Strictly conserved charged residues among polygalacturonases (Asp-180, Asp-201, Asp-202, His-223, Arg-256, and Lys-258) were subjected to site-directed mutagenesis in Aspergillus niger endopolygalacturonase II. Specific activity, product progression, and kinetic parameters (K(m) and V(max)) were determined on polygalacturonic acid for the purified mutated enzymes, and bond cleavage frequencies ...
متن کامل1.68-A crystal structure of endopolygalacturonase II from Aspergillus niger and identification of active site residues by site-directed mutagenesis.
Polygalacturonases specifically hydrolyze polygalacturonate, a major constituent of plant cell wall pectin. To understand the catalytic mechanism and substrate and product specificity of these enzymes, we have solved the x-ray structure of endopolygalacturonase II of Aspergillus niger and we have carried out site-directed mutagenesis studies. The enzyme folds into a right-handed parallel beta-h...
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Glutamate carboxypeptidase II (GCP II) catalyzes the extracellular hydrolysis of the neuromodulator N-acetyl-aspartylglutamate to N-acetyl-aspartate and glutamate. GCP II also hydrolyzes gamma-glutamyl bonds in folylpolyglutamate. The predicted amino acid sequence of GCP II displays similarities to aminopeptidases from Streptomyces griseus and Vibrio proteolyticus, whose crystal structures have...
متن کاملSubsite mapping of Aspergillus niger endopolygalacturonase II by site-directed mutagenesis.
To assess the subsites involved in substrate binding in Aspergillus niger endopolygalacturonase II, residues located in the potential substrate binding cleft stretching along the enzyme from the N to the C terminus were subjected to site-directed mutagenesis. Mutant enzymes were characterized with respect to their kinetic parameters using polygalacturonate as a substrate and with respect to the...
متن کاملSite-Directed Mutagenesis Study
Structural elements of the rat 1.t-opioid receptor important in ligand receptor binding and selectivity were examined using a site-directed mutagenesis approach. Five single amino acid mutations were made, three that altered conserved residues in the ~ 8, and K receptors (Asn 15°t Ala, His297 to Ala, and Tyr326 to Phe) and wo de igned to test for ~i/8 selectivity (lie198 to Val and Va1202 to li...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 2000
ISSN: 0021-9258
DOI: 10.1074/jbc.275.1.691