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Conformational study of angiotensin II
Author(s) -
Shin Young Ah,
Yoo Sungeun
Publication year - 1996
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(199602)38:2<183::aid-bip5>3.0.co;2-r
Subject(s) - intramolecular force , chemistry , crystallography , thermodynamics , perpendicular , chemical physics , computational chemistry , stereochemistry , geometry , mathematics , physics
Conformational free energy calculations using an empirical potential ECEPP/3 (Empirical Conformational Energy Program for Peptides, Version 3) were carried out on angiotensin II (AII) of sequence Asp‐Arg‐Val‐Tyr‐Ile‐His‐Pro‐Phe to find the stable conformations of the free state in the unhydrated and the hydrated states. A conformational analysis of the unhydrated state was carried out using the buildup procedure. The free energy calculation using the hydration shell model was also carried out to obtain the stable conformation of the hydrated state. The calculated stable conformations of AII in both states have a partially right‐handed α‐helical structure stabilized by short‐ and medium‐range interactions. The similarity between the lowest free energy conformations of the unhydrated and hydrated states suggests that the hydration might not be important to stabilize the overall conformation of AII in a free state. The absence of any intramolecular interaction of the Tyr side chain suggests the possible interaction of this residue with the receptor. In this study, we found that the low free energy conformations contain both the parallel‐plate and the perpendicular‐plate geometries of the His and Phe rings, suggesting the coexistence of both conformations. © 1996 John Wiley & Sons, Inc.