Mechanistic study of CuZn-SOD from Ipomoea carnea mutated at dimer interface: enhancement of peroxidase activity upon monomerization.

摘要: Abstract The enzymatically active monomeric form of CuZn-superoxide dismutase has always been interest to decipher the structure–function relationship in this class enzymes. In present study, spectroscopic and enzymatic characteristics dimeric forms recombinant Ipomoea carnea were made their stability altered catalytic properties. protein was produced through site directed mutagenesis by replacing a conserved hydrophobic leucine with polar lysine residue at dimer-interface. Spectral both (monomer dimer) showed presence novel electronic transitions. Superoxide scavenging activity mutated reduced nearly half found native enzyme. Concomitantly, compared enzyme an increase peroxidase activity. High temperature dependent circular dichroism spectral analysis, differential scanning calorimetric profile, measurement superoxide indicated increased susceptibility higher as form. inhibitor studies like hydrogen peroxide, diethyldithiocarbamate phenylglyoxal also indicate susceptibility, which might be due to, arrangement residues consequence mutation. Molecular modeling MD simulation further that specific mutation induces loss interaction dimer interface, resulting observed instability Increased peroxidative enzyme, upon monomerization may have physiological implication essentially high concentration H2O2, case plant cells specifically under stress conditions.