Comparative studies on the dynamics of crosslinked insulin

Area of Science:

• Biochemistry
• Structural Biology
• Computational Chemistry

Background:

• Insulin's structure is critical for its biological activity.
• Crosslinking insulin analogs, such as diaminosuberoyl insulin (DASI), are investigated for therapeutic purposes.
• Understanding the dynamic effects of crosslinking is essential for designing effective insulin analogs.

Purpose of the Study:

• To investigate the influence of N-terminal A chain and C-terminal B chain crosslinking on insulin dynamics.
• To compare the molecular dynamics of crosslinked insulin (DASI), unlinked insulin (ULKI), and native insulin.
• To elucidate the structural basis for the reduced biological potency of A1-B29-crosslinked insulins.

Main Methods:

• Molecular dynamics simulations were performed on crosslinked insulin (DASI) and unlinked insulin (ULKI).
• Simulations included analysis of monomers and dimers to account for crystal packing and quaternary interactions.
• Simulated dynamics were compared against previous simulations of native insulin.

Main Results:

• DASI simulations showed general similarity to native insulin, with reduced flexibility in crosslink-connected segments.
• ULKI simulations closely resembled native insulin dynamics after bridge removal.
• The crosslink's influence extended throughout the molecule but preserved main structural features.

Conclusions:

• The crosslink in DASI restricts the C-terminal B chain's displacement, crucial for receptor interaction.
• Partial shielding of binding residues by the crosslink contributes to reduced biological potency.
• Molecular dynamics simulations provide insights into the structural consequences of insulin crosslinking.