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Conformational studies on a synthetic C‐terminal fragment of the α subunit of G S proteins
Author(s) -
Albrizio Stefania,
D'Ursi Annamaria,
Fattorusso Caterina,
Galoppini Claudia,
Greco Giovanni,
Mazzoni Maria R.,
Novellino Ettore,
Rovero Paolo
Publication year - 2000
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(200009)54:3<186::aid-bip50>3.0.co;2-2
Subject(s) - chemistry , conformational isomerism , turn (biochemistry) , stereochemistry , nuclear magnetic resonance spectroscopy , hexafluoroacetone , molecular dynamics , protein secondary structure , nuclear overhauser effect , peptide , two dimensional nuclear magnetic resonance spectroscopy , crystallography , protein structure , molecular model , molecule , computational chemistry , biochemistry , organic chemistry
It has recently been reported that synthetic peptides corresponding to the C‐terminal sequence of Gα, can be used to study the molecular mechanisms of interaction between this protein and G protein coupled receptors (Hamm et al., Science, 1988, Vol. 241, pp. 832–835). A conformational analysis on a 11 amino acids peptide from the Gα S C‐terminus, Gα S (384–394) (H‐QRMHLRQYELL‐OH), was performed by nmr spectroscopy and molecular modeling methods. Two‐dimensional nmr spectra, recorded in hexafluoroacetone/water, a mixture with structure stabilizing properties, showed an unusually high number of nuclear Overhauser effects, forming significative pattern to the drawing of a secondary structure. Conformations consistent with experimental NOE distances were obtained through molecular dynamics and energy minimization methods. These calculations yielded two stable conformers corresponding to an α‐turn and a type III β‐turn involving the last five C‐terminal residues. Interestingly, the α‐turn conformation was found to overlap with good agreement the crystallographic structure of the same fragment in the Gα S protein. © 2000 John Wiley & Sons, Inc. Biopoly 54: 186–194, 2000