NMR Studies of Hemoproteins

Abstract

In the foregoing lecture on “NMR Studies of Structure and Conformation in Peptides and Proteins” some NMR spectral phenomena relating to the spatial arrangement of the polypeptide chains had been introduced. In this context it was mentionned that certain non-bonding interactions between different segments of a polypeptide chain in the interior of a globular protein molecule can result in rather outstanding chemical shifts of the NMR of individual groups of protons, which can then be used as natural NMR probes for studies of the protein conformations. This will now be illustrated by some experiments with hemoproteins. Molecules of this class of conjugated proteins possess some particularly interesting NMR features because they contain one or several iron porphyrin complexes per molecule, which can greatly affect the NMR spectra both in the diamagnetic and paramagnetic electronic states of the heme iron.