Nuclear magnetic resonance investigation of the electronic structure of deoxymyoglobin

The heme methyl resonances of sperm whale high-spin ferrous or deoxymyoglobin, Mb, have been assigned by a combination of 1 H and 2 H NMR of the protein reconstituted with specifically deuterated hemes. The complete methyl assignments were carried out on deoxyMb with the native protoheme in both the equilibrium orientation and the reversed orientation differing by 180 o rotation about the α, γ-moo axis that is populated transiently upon assembly of apomyoglobin with protoheme. The 1 H NMR spectra of deoxyMb reconstituted with a variety of synthetic hemes also lead to specific assignment of pyrrole proton signals