3D structure prediction, dynamic investigation and rational construction of an epitope-masked thermostable bovine hyaluronidase

Abstract

Hyaluronidase (HAase) from bovine testes (BTH) has long been used in broad pharmaceutical areas, while it is associated with drawbacks in aspects of solubility, immunogenicity and pharmacokinetics. These issues can be addressed by gaining structural insights and designing rational modifications to the enzyme structure, as proposed in this study. A 3D structural model was built for HAase and underwent 40 ns of molecular dynamic simulation to examine its thermostability under normal, melting, and extreme conditions. The enzyme activity of BTH was measured against temperature and pH by kinetic assays. The interaction of bovine HAase with HA and chondroitin was defined by molecular docking. Furthermore, immunogenic properties of the enzyme were explored by immunoinformatics. Thermal effects on bovine HAase structural model and the HAase interactions with its substrates were described. We identified some B- and T-cell epitopes and showed that the protein could be recognized by human immune receptor molecules. Epitope masking by adding polyethylene glycol (PEG) to amine groups of residues presenting on the surface of the protein structure was adopted as a surface modification to enhance pharmacological properties of BTH. Assays showed that PEGylated BTH had higher thermostability and similar activity compared to the native enzyme.

Keywords: Chemical modification; Hyaluronidase from bovine testes; Surface-epitope masking.