Sankarapandi S, Sukumar M, Balaram P, Manoharan P T
Department of Chemistry, Indian Institute of Technology, Madras.
Biochem Biophys Res Commun. 1995 Aug 15;213(2):439-46. doi: 10.1006/bbrc.1995.2151.
Electron spin-spin exchange interaction in biradicals has been examined for its potential usefulness in the conformational analysis of peptides in solution. Three peptides with high propensity to adopt beta-turn conformations in solution, Boc-Cys-Pro-Xxx-Cys-NHMe (Xxx = Leu, 1; Xxx = Aib, 2; Xxx = Tyr, 3), have been modified into biradicals by spin labeling the thiols groups. Analysis of electron spin resonance spectra of these peptides in a variety of solvents and at different temperatures suggests that the population of folded conformations follows the order 2 > 1 > 3.
