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Conformational analysis of endomorphin-2 by molecular dynamics methods.
Balázs Leitgeb1, Ferenc Otvös, Géza Tóth
1Institute of Biochemistry, Biological Research Center of the Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary. leitgeb@rosi.szbk.u-szeged.hu
Biopolymers
|April 1, 2003
Summary
Endomorphin-2, a potent mu-opioid agonist, adopts specific conformations including beta-turns and gamma-turns. These structures are stabilized by intramolecular hydrogen bonds, influencing its receptor interaction.
Area of Science:
- Computational Chemistry
- Molecular Modeling
- Pharmacology
Background:
- Endomorphin-2 (EM2) is a highly potent and selective mu-opioid receptor agonist.
- Understanding EM2's conformation is crucial for elucidating its interaction with the mu-opioid receptor.
Purpose of the Study:
- To perform a comprehensive conformational analysis of Endomorphin-2 (EM2).
- To investigate the influence of peptide bond isomerism (cis/trans) and protonation state on EM2 conformation.
Main Methods:
- Simulated annealing (SA) and molecular dynamics (MD) simulations were employed for conformational analysis.
- Molecular modeling considered both neutral and charged states of EM2.
- Simulations incorporated restraints for cis/trans Pro peptide bonds and also unrestrained simulations.
Main Results:
- Preferred conformational states were identified and visualized using Ramachandran plots.
- Analysis revealed specific populations of aromatic side chain conformations (chi(1) space) and key interatomic distances.
- Identified secondary structural elements include beta-turns and gamma-turns, stabilized by intramolecular and bifurcated hydrogen bonds.
Conclusions:
- EM2 adopts preferred conformations characterized by specific turns and side-chain arrangements.
- Intramolecular hydrogen bonds play a significant role in stabilizing these conformations.
- These findings provide insights into the structural basis of EM2's potent mu-opioid receptor agonism.