CONTRIBUTION OF CATION-Π INTERACTION AND ITS EFFECT ON THE STRUCTURAL STABILITY OF LACCASE ENZYMES-A COMPUTATIONAL STUDY

Abstract

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 cation-
π interactions are important in locating one or more of such centers. We have also determined the
stability of each enzymes by its ΔG 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.