Characterization of recombinant pumpkin 2S albumin and mutation studies to unravel potential DNA/RNA binding site

Biochem Biophys Res Commun. 2021 Sep 29;580:28-34. doi: 10.1016/j.bbrc.2021.09.076. Online ahead of print.ABSTRACTThe native pumpkin 2S albumin, a multifunctional protein, possess a variety of potential biotechnologically exploitable properties. The present study reports the characterization of recombinant pumpkin 2S albumin (rP2SA) and unraveling of its potential DNA/RNA binding site. The purification and characterization of the rP2SA established that it retains the characteristic α-helical structure and exhibited comparable DNase, RNase, antifungal and anti-proliferative activities as native protein. In vitro studies revealed that rP2SA exhibits potent antiviral activity against chikungunya virus (CHIKV) at a non-toxic concentration with an IC50 of 114.5 μg/mL. In silico studies and site-directed mutagenesis were employed to unravel the potential DNA/RNA binding site. A strong positive charge distribution due to presence of many arginine residues in proximity of helix 5 was identified as a potential site. The two of the arginine residues, conserved in some 2S albumins, were selected for the mutation studies. The mutated forms of recombinant protein (R84A and R91A) showed a drastic reduction in DNase and RNase activities suggesting their presence at binding site and involvement in the nuclease activity. A metal binding site was also identified adjacent to DNA/RNA binding site. The present study demonstrated the structural and functional integrity of the rP2SA and reports p...
Source: Biochemical and Biophysical Research communications - Category: Biochemistry Authors: Source Type: research