Site-directed mutation of a laccase from Thermus thermophilus: effect on activity profile
2012
Liu, X., Sichuan University, Chengdu (China). College of Life Sciences, Department of Biochemistry | Tian, M., Sichuan University, Chengdu (China). College of Life Sciences, Department of Biochemistry | Liu, K., Sichuan University, Chengdu (China). College of Life Sciences, Department of Biochemistry
A site-directed mutant R453T of a laccase from Thermus thermophilus HB27 (Tth-laccase) was constructed in order to investigate the effect on laccase catalytic properties. The mutated gene was cloned and overexpressed in Escherichia coli. Nickel-affinity purification was achieved and followed by copper ion incorporation. The mature mutated enzyme was quantitatively equal to the wild type. A photometric assay based on the oxidation of the substrate 2,2-azino-bis-(3- ethylbenzthiazoline-6-sulfonate) (ABTS) was employed in comparison with the wild-type Tth-laccase on catalytic properties. The R453T mutant exhibited improvement in substrate affinity and specific activity at room temperature, whereas those parameters were not significantly influenced when the temperature increased up to 65 deg C or higher. The mutant had better catalytic activity than that of the wild type at acidic pH. Investigated by circular dichroism spectroscopy, the mutant Tth-laccase displayed similar profiles at low and high temperatures.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by Matica Srpska Library