It has recently been reported that synthetic peptides corresponding to the C-terminal sequence of G alpha, 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 G alpha(S) C-terminus, G alpha(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 alpha-turn mid a type III beta-turn involving the last five C-terminal residues. Interestingly the alpha-turn conformation was found to overlap with good agreement the crystallographic structure of the same fragment in the G alpha(S) protein. (C) 2000 John Wiley & Sons, Inc.
|Autori:||Albrizio S; D'Ursi A; Fattorusso C; Galoppini C; Greco G; Mazzoni M; Novellino E; Rovero P|
|Titolo:||Conformational studies on a synthetic C-terminal fragment of the alpha subunit of G(S) proteins|
|Anno del prodotto:||2000|
|Digital Object Identifier (DOI):||10.1002/1097-0282(200009)54:3<186::AID-BIP50>3.0.CO;2-2|
|Appare nelle tipologie:||1.1 Articolo in rivista|