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Disulfide linkage Raman markers: a reconsideration attempt
Author(s) -
Hernández Belén,
Pflüger Fernando,
LópezTobar Eduardo,
Kruglik Sergei G.,
GarciaRamos José V.,
SanchezCortes Santiago,
Ghomi Mahmoud
Publication year - 2014
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4521
Subject(s) - raman spectroscopy , disulfide bond , chemistry , crystallography , dihedral angle , carbon disulfide , moiety , conformational isomerism , molecule , stereochemistry , hydrogen bond , organic chemistry , physics , biochemistry , optics
During the last decades, Raman spectroscopy has been routinely used for probing the conformational features of disulfide linkages in peptides and proteins. However, the interpretation of disulfide Raman markers is currently performed by a simple rule derived from the earliest observations on dialkyl disulfides. More precisely, this rule consists of the following: (1) in analyzing the Raman bands in the 550–500 cm −1 region ascribed to disulfide bond stretch motion, namely, ν (S‐S), and (2) assigning the three types of Raman markers observed at ~500, ~520, and ~540 cm −1 to three families of rotamers defined along the three successive bonds of the ‐C‐S‐S‐C‐ moiety, referred to as ggg , ggt , and tgt . In this report, we attempt to show that an accurate analysis of disulfide vibrational features needs the use of the five torsion angles ( χ 1 , χ 2 , χ 3 , χ 2 ', and χ 1 ') along the five successive bonds joining the two α ‐carbon atoms in the cystine (Cys‐Cys) unit. The present work is inspired by the disulfide conformational investigations performed by a statistical scan of numerous protein crystal and nuclear magnetic resonance data, taking into account the handedness (right and left) of a disulfide bridge, its spatial shape (Staple, Hook, and Spiral), as well as the signs of the two extreme torsion angles χ 1 and χ 1 '. It appears that the combined use of the old and recent conformational notations allows a more accurate structural and vibrational analysis of disulfide linkage. Copyright © 2014 John Wiley & Sons, Ltd.