The structures and properties of proton- and alkali-bound cysteine dimers

• Published in: Physical chemistry chemical physics : PCCP Vol. 18; no. 6; p. 4704
• Main Authors: Ieritano, Christian, Carr, Patrick J J, Hasan, Moaraj, Burt, Michael, Marta, Rick A, Steinmetz, Vincent, Fillion, Eric, McMahon, Terrance B, Scott Hopkins, W
• Format: Journal Article
• Language: English
• Published: England 14-02-2016
• Subjects: Alkalies - chemistry; Cysteine - chemistry; Dimerization; Molecular Structure; Protons; Spectrum Analysis
• ISSN: 1463-9084
• DOI: 10.1039/c5cp07414b

The proton-, lithium-, and sodium-bound cysteine dimers have been investigated in a joint computational and experimental infrared multiple photon dissociation (IRMPD) study. IRMPD spectra in the 1000-2000 cm(-1) region show that protonation is localized on an amine group, and that intermolecular hydrogen bonding occurs between the protonated amine and the carbonyl oxygen of the neutral Cys moiety. Alkali-bound dimers adopt structures reminiscent of those observed for the monomeric Cys·Li(+) and Cys·Na(+) species. Calculations of the heavier Cys2·M(+) (M = K, Rb or Cs) species suggest that these are significantly less strongly bound than the lighter (M = H, Li, or Na) dimers.