Characterization of alkaline transitions in ferricytochrome c using carbon-deuterium infrared probes

P. Weinkam, J. Zimmermann, L.B. Sagle, S. Matsuda, P.E. Dawson, P.G. Wolynes, F.E. Romesberg, Biochemistry (2008) 47:13470-13480.
pubpic2008weinkamWe use a combination of experiments and simulations to provide a high-resolution view of the structural changes in cyt c with increasing alkaline conditions. Alkaline-induced transitions were characterized under equilibrium conditions by monitoring IR absorptions of carbon−deuterium chromophores incorporated at Leu68, Lys72, Lys73, Lys79, and Met80. The data suggest that at least four intermediates are formed as the pH is increased prior to complete unfolding of the protein.