HETERONUCLEAR MULTIPLE-QUANTUM COHERENCE NMR-SPECTROSCOPY OF PARAMAGNETIC HEME AND CYTOCHROME-C-551

Heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond coherence (HMBC), and heteronuclear multiple-quantum relay (HMQR) NMR spectra were obtained for the bis(cyano) complex of iron(III) protoporphyrin IX (dicyanoheme b), its free base, horse heart ferricytochrome c, and Pseudomonas aeruginosa ferricytochrome c-551. For the heme it was possible to assign all the protons and carbons. For the hemoproteins, it was possible to assign select protons and carbon atoms near the paramagnetic iron that can act as active-site probes in both the H-1 and C-13 frequency regions.