Electrostatic Interactions in Docking a 3D Model of Bovine Testicular Hyaluronidase with a Chondroitin Sulfate Trimer and a Heparin Tetramer

Abstract

The molecular docking of a 3D-model of bovine testicular hyaluronidase with glycosaminoglycan ligands is performed. A chondroitin sulfate trimer and a heparin tetramer were used as ligands. Methods of computational chemistry are applied to elucidate the regulation of hyaluronidase functioning in an organism when the heparin ligand inactivates the biocatalyst, and the chondroitin sulfate ligand protects the enzyme structure. Eight ligand binding sites are identified on the molecular surface of the enzyme, each of which is equally capable of interacting with chondroitin sulfate trimers and heparin tetramers via electrostatic interactions. It is found that reversible and irreversible conformational changes in the enzyme 3D structure can occur depending on the positioning of negatively charged ligands on its globule (under different conditions, they can either stabilize or inactivate the biocatalyst). Binding sites whose occupancy is sufficient for preventing irreversible deformations of the enzyme conformation upon introducing the heparin ligand into the active site are identified on the molecular surface of hyaluronidase. The interaction of glycosaminoglycan ligands with hyaluronidase is mainly determined by electrostatic forces.