Localized Control of Ligand Binding in Hemoglobin: Effect of Tertiary Structure on Picosecond Geminate Recombination

• Published in: Science (American Association for the Advancement of Science) Vol. 229; no. 4709; pp. 187 - 190
• Main Authors: Friedman, J. M., Scott, T. W., Fisanick, G. J., Simon, S. R., Findsen, E. W., Ondrias, M. R., Macdonald, V. W.
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 12.07.1985; American Association for the Advancement of Science
• Subjects: Animals; Biochemistry; Biological and medical sciences; Delay lines; Fishes; Fundamental and applied biological sciences. Psychology; Genetic recombination; Heme - metabolism; Hemoglobin; Hemoglobins; Hemoglobins, Abnormal - genetics; Hemoglobins, Abnormal - metabolism; Humans; Interactions. Associations; Intermolecular phenomena; Ligands; Ligands - metabolism; man; Molecular biophysics; Oxygen - metabolism; Photolysis; Pisces; Protein Binding; Protein Conformation; Proteins; Raman scattering; Reactivity; recombination; Reptilia; Research facilities; tertiary structure; Picosecond; Oxygen; Photolysis; Association dissociation; Ligand; Quaternary structure; Hemoglobin; Raman spectrometry; Photodissociation; Carbon
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.4012316

The picosecond geminate rebinding of molecular oxygen was monitored in a variety of different human, reptilian, and fish hemoglobins. The fast (100 to 200 picoseconds) component of the rebinding is highly sensitive to protein structure. Both proximal and distal perturbations of the heme affect this rebinding process. The rebinding yield for the fast process correlates with the frequency of the stretching motion of the iron-proximal histidine mode (v$_{Fe-His}$) observed in the transient Raman spectra of photodissociated ligated hemoglobins. The high-affinity R-state species exhibit the highest values for v$_{Fe-His}$ and the highest yields for fast rebinding, whereas low affinity R-state species and T-state species exhibit lower values of v$_{Fe-His}$ and correspondingly reduced yields for this geminate process. These findings link protein control of ligand binding with events at the heme.