Site-directed mutagenesis at position 396 to enhance the thermo-stability of RuBisCO activase

Abstract

Rubisco activase (Rca) is a catalytic chaperone that remodels Rubisco's active site, facilitates inhibitor release, and restores catalytic competence. Changes in the chloroplast environment generated by changes in light levels entering the leaf, including redox status and the adenosine diphosphate (ADP)/adenosine triphosphate (ATP) ratio, influences activity and its effect on Rubisco activation and photosynthesis. Three Rca protein isoforms are encoded by the Triticum aestivum (wheat) genome: 1β (42.7 kDa), 2β (42.2 kDa), and 2α (46.0 kDa). One site-directed mutant were designed to elucidate if differences in the amino acid sequences between Rca of wheat and thermotolerant cultivar. The effect of IPTG concentration was checked, and it was found that 0.9mM is the best suited for the induction of mutant protein.