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Design, synthesis, and conformation of a model peptide of endothelin with cystine‐stabilized α‐helix motif
Author(s) -
Mihara Hisakazu,
Tomizaki KinYa,
Nishino Norikazu,
Fujimoto Tsutomu,
Tamaoki Haruhiko,
Kobayashi Yuji
Publication year - 1994
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/bip.360340714
Subject(s) - chemistry , peptide , stereochemistry , cystine , helix (gastropod) , crystallography , aqueous solution , endothelin 3 , amide , ethylene glycol , peptide sequence , cysteine , endothelin receptor , organic chemistry , biochemistry , endothelins , ecology , receptor , snail , biology , enzyme , gene
A model 16‐peptide of endothelin‐1 (MET‐1), which has the minimized sequence homology to the corresponding pan of endothelin‐1 (ET‐1), was designed to confirm the cystine‐stabilized α‐helix motif. The model structure consists of an extended structure, a β‐turn part, and an α‐helix structure that is stabilized by two disulfide bonds. The α‐helix segment was designed to emphasize the amphiphilic nature. In order to combine the extended structure and the α‐helix segment, a D ‐Ala‐Pro sequence was selected to fix the β‐turn. The model endothelin 16‐peptide amide was synthesized by solid‐phase synthesis on a 4‐methylbenzhydrylamine resin. Its conformation was examined by CD and two‐dimensional (2D) 1 H‐nmr measurements. MET‐1 showed similar CD patterns to ET‐1 in both buffer and 50% aqueous trifluoroethanol solution. The 2D nmr experiments in 50% aqueous ethylene glycol revealed that MET‐1 closely resembles the conformation of ET‐1 with an extended structure, an α‐helix, and a β‐turn unit in the same position of the sequence. Furthermore, model peptides without disulfide bond(s) could not assume a stable structure in aqueous solution, while they did have similar α‐helical content in 50% trifluoroethanol with MET‐1. When the two disulfide bridges were simultaneously formed, the peptide with the correct disulfide bonds (MET‐1) was obtained in threefold excess to the isomer (apamin type. MET‐2). These findings obtained by the modeling of ET‐1 showed an important role for the stabilization of peptide conformation with disulfide bonds. © 1994 John Wiley & Sons, Inc.