Thermostabilization of Hyaluronidase by Chondroitin Ligands in Molecular Docking

Abstract

Speedup of present high-molecular drug derivatives developments is based on the computational methods harmonic application. Such glycosidase as hyaluronidase has been functionated among multifarious glycosaminoglycan microenvironment in blood circulation of organism. It is important for elucidation of action mechanism of biosystem components (on vascular wall) and productive obtaining of hyaluronidase derivatives of cardiological destination the using of computer aided calculations for investigation of protein-glycosaminoglycan interactions. The aim of our study became the molecular docking fulfillment for 3D model of bovine testicular hyaluronidase with short-chain dimer and trimer chondroitin ligands. We used the molecular docking of hyaluronidase with chondroitin ligands for theoretical determination of biocatalyst conformational stability. At temperatures higher than 300 K free/native hyaluronidase (without ligands) displayed conformational transitions leading to its inactivation. Predominant manifestation of these transitions was an irreversible attraction developing between the protein area proximate to Glu-105, on the one hand, and to Arg-59 and Arg-96, on the other. Lowering of temperature did not restore the initial 3D structure of hyaluronidase. Binding of chondroitin ligands at ch 6, ch 3 and ch 1 sites stabilized the enzyme, increasing its denaturation temperature by 10°C. The highest degree of stabilization was achieved after chondroitin binding to ch 6. This effect was higher than that for chondroitin sulfate trimers concerning the enzyme inhibition by heparin tetramer, which requires binding of 4-5 chondroitin sulfate ligands to the enzyme surface. Molecular docking of 3D model of bovine testicular hyaluronidase with chondroitin dimers and trimers has revealed eight sites for their binding to the enzyme surface. At biological concentrations of these ligands the most important binding sites for them are ch 6, ch 3 and ch 1. Binding at these sites induces a reversible deformation of the protein 3D structure. Interactions between 3D model of bovine hyaluronidase with chondroitin ligands are based predominantly on electrostatic forces. Chondroitin ligands stabilized 3D structure of hyaluronidase after binding predominantly at chondroitin 6 as well as chondroitin 3 and chondroitin 1 positions and their effect was higher than chondroitin sulfate upon enzyme inhibition by heparin tetramer. Stabilizing effects of chondroitin and chondroitin sulfate ligands are fundamental for further direct theoretical comparative investigation of impact produced by these ligands.