Individual assignments of the heme resonances in the 360 MHz 1H NMR spectra of cytochrome c-557 from Crithidia oncopelti.

With the use of nuclear Overhauser effects, spin decoupling and saturation transfer experiments individual assignments for numerous resonances of the heme group in the 360 MHz 1H NMR spectra of reduced and oxidized cytochrome c-557 from Crithidia oncopelti were obtained. These data provide direct evidence that the heme substituent in position 2 is a vinyl group. They further show that in spite of the different covalent structures of the heme groups the heme crevice and the electronic heme structure in the oxidized state are nearly identical in cytochrome c-557 and in mammalian cytochromes c.