Structural Ensemble of the Insulin Monomer

Area of Science:

• Biochemistry
• Structural Biology
• Computational Chemistry

Background:

• Monomeric insulin exhibits conformational heterogeneity, influencing biological activity and pharmaceutical formulation stability.
• Understanding the microscopic basis of this heterogeneity is crucial but has been lacking.

Purpose of the Study:

• To investigate the structural ensemble of human insulin monomers using advanced computational methods.
• To elucidate the conformational dynamics and heterogeneity of insulin at a molecular level.

Main Methods:

• All-atom molecular dynamics simulations were employed to model human insulin monomers.
• A comprehensive analysis pipeline was used to examine the resulting structural ensemble.
• Hydrogen-exchange protection factors were estimated and compared with experimental data.

Main Results:

• 60% of simulated structures showed disorder, including A-chain N-terminal helix melting and B-chain terminus detachment.
• Partial melting and extension of the B-chain helix were observed, alongside β-turn region heterogeneity.
• Estimated hydrogen-exchange protection factors aligned with experimental KP-insulin data, though unfolded states were underestimated.

Conclusions:

• The study provides a microscopic understanding of human insulin monomer conformational heterogeneity.
• Results explain experimental observations of amide site exchange and offer insights into insulin function and stability.
• Findings have implications for understanding insulin's biological roles and developing more stable insulin formulations.