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Conformational study of angiotensin II
1Korea Research Institute of Chemical Technology, DaeDoeg Science Complex, Dae-Jeon, Korea.
Biopolymers
|February 1, 1996
Summary
Computational analysis of angiotensin II reveals stable, partially helical conformations in both hydrated and unhydrated states. Hydration appears less critical for overall structure, with Tyr side chains potentially interacting with receptors.
Area of Science:
- Computational chemistry
- Molecular modeling
- Biophysics
Background:
- Angiotensin II (AII) is a key peptide hormone involved in blood pressure regulation.
- Understanding AII's conformational states is crucial for drug design and molecular interactions.
Purpose of the Study:
- To determine the stable conformations of angiotensin II in both unhydrated and hydrated states using free energy calculations.
- To investigate the influence of hydration on AII's overall structure and specific residue interactions.
Main Methods:
- Empirical Conformational Energy Program for Peptides, Version 3 (ECEPP/3) was used for free energy calculations.
- Conformational analysis employed the buildup procedure for the unhydrated state.
- Hydration shell model was utilized for the hydrated state analysis.
Main Results:
- Stable, partially right-handed alpha-helical conformations were identified in both unhydrated and hydrated AII.
- Low free energy conformations exhibited both parallel-plate and perpendicular-plate geometries for His and Phe rings.
- The Tyr side chain showed no intramolecular interactions, suggesting potential receptor binding.
Conclusions:
- Hydration may not significantly alter the overall stable conformation of angiotensin II in its free state.
- The identified conformations provide insights into AII's molecular behavior and potential receptor interactions.
- The coexistence of different His and Phe ring geometries suggests conformational flexibility relevant to binding.