jp001692g_si_001.pdf (486.94 kB)
Theoretical Studies of the Radiation Products of Hydroxyproline
journal contribution
posted on 2000-08-25, 00:00 authored by Fuqiang Ban, James W. Gauld, Russell J. BoydThe radiation products of hydroxyproline have been investigated using density functional theory. In the resulting
radicals, the choice of the apical ring atom is found to be dependent on the nature and strength of the
intramolecular hydrogen bonding. The observed hyperfine couplings previously assigned to two zwitterionic
conformers of the hydroxyproline primary radical anion are found to be better described by its nonzwitterionic
isomers and corresponding neutral protonated isomers. Similarly, the observed hyperfine couplings for radicals
formed by cleavage of the Cα−N bond (deamination) are in closest agreement with those calculated for their
neutral forms. Theoretical proton hyperfine couplings support the experimental assignment of the radical
cation formed by decarboxylation and the radicals resulting from hydrogen abstraction from the C2 and C3
positions. The proton hyperfine couplings are sensitive to the conformations of the radicals, which, in turn,
are highly dependent upon the extent of intramolecular hydrogen bonding.