Contribution of Cation-π Interaction and Its Effect on the Structural Stability of Laccase Enzymes-a Computational Study

The energy contribution resulting from cation-π interactions and free energy of folding has been computed for 18 laccase enzymes. The contribution of these cation-π interacting residues in secondary structure involvement, solvent accessibility, stabilization centers and structural stability has been evaluated. Secondary structure of the cation-π involving residues show that, Arg and Lys prefers to be in strand and coil structures respectively. Among the π residues, Phe and Tyr prefer to be in coil whereas Trp prefers to be in strand. Among the cation-π interacting residues Arg and Lys were in the exposed regions. Phe and Tyr were in the partially buried region and Trp in the fully buried region. Stabilization centers for these proteins showed that all the five residues found in cationπ interactions are important in locating one or more of such centers. We have also determined the stability of each enzymes by its ∆G value. On the whole, the results presented in this work suggest that Bacillus Subtilis Cota Laccase Adduct with ABTS (1UVW) exhibit the highest stability among the entire laccase enzyme studied in this investigation.