Assignments of resonances of the heme and distal amino acid protons in spectra of the CO and O2 complexes of sperm whale myoglobin are reported. These resonances provide information on the conformation of the heme pocket. For oxymyoglobin, the assignments of the heme meso protons disagree with those proposed previously on the basis of partial deuteration experiments. Rapid ring flips about the Cβ-Cγ bond are detected for Phe-CD1. Recent claims for two conformational substrates of valine-E11 in carbonmonoxymyoglobin (Bradbury, J.H. and Carver, J.A. (1984) Biochemistry 23, 4905-4913) are shown to be in error. The pK of His-97 (FG3) in carbonmonoxymyoglobin has been determined (pK = 5.9). This residue appears to influence many spectroscopic properties of myoglobin. The distal His-E7 in carbonmonoxymyoglobin has pK < 5.0. Differences in the heme pocket conformation in the CO complexes of myoglobin and leghemoglobin are discussed. These differences may be influential in O2 and CO association reactions.
|Number of pages||11|
|Journal||Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular|
|Publication status||Published - 29 Nov 1985|
- (Sperm whale)
- Amino acid
- Heme group
- Resonance assignment