Computational Biochemistry of Congo Red Dye Biodegradation by Laccases
Bioremediation. MFCC. DFT. Intermolecular interactions. Congo red dye. Lacase from Pycnoporus sanguineus. Lacase from Tratametes versicolor.
The worldwide increase in urbanization and industrial activities has led to the production and introduction of contaminating molecules into ecosystems. Pollution of water bodies by untreated sewage causes numerous damages to species living in the aquatic environment. Biotechnological processes and physical, chemical, and biological strategies have been developed to remove these contaminants from anthropogenically polluted waters. From the perspective of bioremediation, lacases are enzymes capable of degrading phenolic, aromatic, and non-aromatic compounds, including synthetic dyes from the textile industry. In this context, the present work proposes to analyze the intermolecular contacts of Congo red dye coupled to lacases from Tratametes versicolor (CR -LacTv) and Pycnoporus sanguineus (CR -LacPs) qualitatively (type of chemical bonding), quantitatively (interaction energy), and comparatively, including the identification of interaction patterns. To describe the individual ligand-receptor type binding energies present in these biocomplexes, we used the molecular fractionation scheme with conjugated caps (MFCC) in the framework of density functional theory (DFT). The results indicate a higher affinity of the Congo red dye for the lacase of Pycnoporus sanguineus. In this case, the dye interacts with LacPs (LacTv) with a binding energy of -38.26 kcal/mol (-19.26 kcal/mol), with 63.3% (63.6%) of the intermolecular contacts occurring with the amino acids of the receptor from the iii (i) region of this ligand. The major residues of the CR -LacPs (CR -LacTv) complex are ARG161, PHE162, GLY392, GNL160, SER393, PRO391, PHE265, and GLY266 (PHE162, ALA161, GLY266, ALA393, PHE 265, PRO391, PRO160, GLY392), in which we highlight the existence of six (five) large hydrogen bonds and two (three) hydrophobic contacts in CR -LACPs (LacTv). The structural and energetic description of the interactions of the biocomplexes in question helps to understand the differences in terms of stability and efficacy of enzymes of the same family but different organisms. Consequently, it will allow studies to increase the effectiveness of bioremediation promoted by such enzymes following targeted point changes.