Modulation of protein function by exogenous ligands in protein cavities: CO binding to a myoglobin cavity mutant containing unnatural proximal ligands.

A variety of heterocyclic ligands can be exchanged into the proximal cavity of sperm whale myoglobin mutant H93G, providing a simple method for introduction of the equivalent of unnatural amino acid side chains into a functionally critical location in this protein. These modified proteins bind CO on the distal side. 1H NMR data on H93G(Im)CO, where Im is… (More)