Multi-conformational peptide dynamics derived from NMR data: a new search algorithm and its application to antamanide

Area of Science:

• Biochemistry
• Structural Biology
• Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

• Understanding biomolecular dynamics is crucial for elucidating function.
• High-resolution NMR spectroscopy provides insights into molecular structure and dynamics.
• Characterizing multiple conformations and their exchange rates remains a challenge.

Purpose of the Study:

• To present the MEDUSA algorithm for determining multiple biomolecular conformations in solution.
• To enable the calculation of exchange rate constants for molecular dynamics.
• To apply the algorithm to a cyclic decapeptide for structural analysis.

Main Methods:

• Utilizing experimental high-resolution NMR data, including NOESY, ROESY, J-coupling constants, and T1 rho relaxation measurements.
• Generating ensembles of structures consistent with NMR-derived parameters.
• Employing the MEDUSA search algorithm to analyze dynamic exchange between conformations.

Main Results:

• The MEDUSA algorithm successfully determines multiple conformations of biomolecules in solution.
• Exchange rate constants between 10(3) and 10(7) s-1 were determined.
• Application to antamanide revealed characteristic radio-frequency field dependence of T1 rho relaxation rates for specific protons, explained by dynamical exchange between two structures.

Conclusions:

• MEDUSA is an effective tool for characterizing biomolecular ensembles and dynamics.
• The algorithm provides insights into the conformational landscape of molecules in solution.
• The study demonstrates the capability of MEDUSA to explain complex relaxation phenomena through molecular dynamics.