Effect of N-glycosylation on horseradish peroxidase structural and dynamical properties.

The effect of different branching types of glycosylation on the structure and dynamics of the horseradish peroxidase (HRP) and an engineered split horseradish peroxidase (sHRP) was studied using all-atom molecular dynamics (MD) simulations. Although tertiary structures of both proteins are stable in the presence, as well as in the absence of glycans, differences in the dynamical properties regarding the presence of glycans were noticed. Fluctuations in the protein structure along both proteins are decreased when glycosylation is introduced. We identified two main regions that are affected the most. The peripheral region is impacted directly by glycans and the central region within the active site with a propagated effect of glycans. Since the mentioned central region in the glycoprotein is not surrounded by glycans and is close to the heme, it is easily approachable to the solvent and substrate. An influence of the glycan presence on the electrostatic potential of the protein and on the heme cofactor was also observed. Altogether, this work presents a global and local analysis of the glycosylation influence on HRP protein's structural and dynamical properties at a molecular level.