(342s) Gaining Mechanistic Insights into the Influence of O-Linked Glycosylation on Insulin Properties with Molecular Dynamics

Insulin has been widely used as a peptide drug to treat diabetes by promoting the absorption of glucose from the blood. In recent years, there has been an increased interest in the development of the insulin drug for oral administration to address the low patients compliance caused by frequent subcutaneous injections. However, the research in this field has been challenging due to insulin’s low permeability across the intestinal epithelium upon oligomerization and the susceptibility to proteases in the digestive system of the human body, which lead to overall low absorption efficiency. O-linked glycosylation, as applied in a few recent experimental studies, has been considered one of the most promising approaches to address the challenge. Attachment of proper saccharides to the glycosylation sites in the tail region can enhance insulin’s proteolytic stability and decrease its oligomerization propensity without sacrificing biological activity. However, with a lack of mechanistic insights into how the insulin properties are improved by O-glycosylation, the strategies for glyco-insulin design remain elusive. To gain a better understanding at the molecular level, we performed long (2 microseconds) molecular dynamics (MD) simulations of the insulin glycoforms investigated in previous experimental studies. These insulin glycoforms were based on five different crystal structures of insulin wildtype. We present an analysis of experimental observables, including cleavage site solvent accessible surface area, secondary structure propensity, and peptide flexibility to predict the proteolytic stability and dimerization propensity of glycoforms and use these observables to predict behaviors of proposed glycoforms.