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. 1978 Feb;75(2):564–568. doi: 10.1073/pnas.75.2.564

Model compounds for the T state of hemoglobin.

J P Collman, J I Brauman, K M Doxsee, T R Halbert, K S Suslick
PMCID: PMC411295  PMID: 273219

Abstract

O2 binding to a series of ferrous and cobaltous "picket fence" porphyrins is reported. N-Methylimidazole and covalently attached imidazoles gives O2 binding to ferrous porphyrins with deltaH degrees =-16.2 kcal/mol (-67.7 kJ/mol) and deltaS degrees =-40 eu (standard state, 1 atmosphere O2). Similar studies with cobaltous porphyrins yield deltaH degrees =- 12.8 kcal/mol (-53.5 kJ/mol) and deltaS degrees =- 39 eu. These values match well those of myoglobin and isolated subunits of hemoglobin and their cobalt reconstituted analogues. 1,2-Dimethylimidazole has been successfully used to mimic the presumed restraint of T state hemoglobin. In direct analogy to the decreased cooperativity shown by cobalt-substituted hemoglobin, model cobalt porphyrins show a smaller decrease in O2 affinity than the analogous iron porphyrins when the axial base is hindered. Thermodynamic data are presented. The molecular mechanism of cooperativity in hemoglobin is discussed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Brault D., Rougee M. Binding of imidazole and 2-methylimidazole by hemes in organic solvents. Evidence for five-coordination. Biochem Biophys Res Commun. 1974 Apr 8;57(3):654–659. doi: 10.1016/0006-291x(74)90596-8. [DOI] [PubMed] [Google Scholar]
  2. Brunori M., Noble R. W., Antonini E., Wyman J. The reactions of the isolated alpha and beta chains of human hemoglobin with oxygen and carbon monoxide. J Biol Chem. 1966 Nov 25;241(22):5238–5243. [PubMed] [Google Scholar]
  3. Collman J. P., Brauman J. I., Halbert T. R., Suslick K. S. Nature of O2 and CO binding to metalloporphyrins and heme proteins. Proc Natl Acad Sci U S A. 1976 Oct;73(10):3333–3337. doi: 10.1073/pnas.73.10.3333. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Collman J. P., Brauman J. I., Suslick K. S. Letter: Oxygen binding to iron porphyrins. J Am Chem Soc. 1975 Nov 26;97(24):7185–7186. doi: 10.1021/ja00857a050. [DOI] [PubMed] [Google Scholar]
  5. Collman J. P., Gagne R. R., Reed C. A., Halbert T. R., Lang G., Robinson W. T. "Picket fence porphyrins." Synthetic models for oxygen binding hemoproteins. J Am Chem Soc. 1975 Mar 19;97(6):1427–1439. doi: 10.1021/ja00839a026. [DOI] [PubMed] [Google Scholar]
  6. Collman J. P., Reed C. A. Syntheses of ferrous-porphyrin complexes. A hypothetical model for deoxymyoglobin. J Am Chem Soc. 1973 Mar 21;95(6):2048–2049. doi: 10.1021/ja00787a075. [DOI] [PubMed] [Google Scholar]
  7. Dwyer P. N., Madura P., Scheidt W. R. Stereochemistry of low-spin cobalt porphyrins. VI. Molecular stereochemistry of (1,2-dimethylimidazole)-alpha, beta, gamma, delta-tetraphenylporphinatochobalt(II). J Am Chem Soc. 1974 Jul 24;96(15):4815–4819. doi: 10.1021/ja00822a018. [DOI] [PubMed] [Google Scholar]
  8. Geibel J., Chang C. K., Traylor T. G. Letter: Coordination of myoglobin active site models in aqueous solution as studied by kinetic methods. J Am Chem Soc. 1975 Oct 1;97(20):5924–5926. doi: 10.1021/ja00853a053. [DOI] [PubMed] [Google Scholar]
  9. Gelin B. R., Karplus M. Mechanism of tertiary structural change in hemoglobin. Proc Natl Acad Sci U S A. 1977 Mar;74(3):801–805. doi: 10.1073/pnas.74.3.801. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Ikeda-Saito M., Yamamoto H., Imai K., Kayne F. J., Yonetani T. Studies on cobalt myoglobins and hemoglobins. Preparation of isolated chains containing cobaltous protoporphyrin IX and characterization of their equilibrium and kinetic properties of oxygenation and EPR spectra. J Biol Chem. 1977 Jan 25;252(2):620–624. [PubMed] [Google Scholar]
  11. Ilgenfritz G., Schuster T. M. Kinetics of oxygen binding to human hemoglobin. Temperature jump relaxation studies. J Biol Chem. 1974 May 10;249(9):2959–2973. [PubMed] [Google Scholar]
  12. Imai K. Allosteric effects in cobaltohaemoglobin as studied by precise oxygen equilibrium measurements. J Mol Biol. 1977 Jan 5;109(1):83–97. doi: 10.1016/s0022-2836(77)80047-8. [DOI] [PubMed] [Google Scholar]
  13. Keyes M. H., Falley M., Lumry R. Studies of heme proteins. II. Preparation and thermodynamic properties of sperm whale myoglobin. J Am Chem Soc. 1971 Apr 21;93(8):2035–2040. doi: 10.1021/ja00737a031. [DOI] [PubMed] [Google Scholar]
  14. Knowles F. C., Gibson Q. H. A gas--liquid equilibration apparatus for quantitative determination of oxygen binding by hemoglobin. Anal Biochem. 1976 Dec;76(2):458–486. doi: 10.1016/0003-2697(76)90341-9. [DOI] [PubMed] [Google Scholar]
  15. Little R. G., Ibers J. A. Stereochemistry of cobalt porphyrins. 3. The structure of 2,3,7,8,12,13,17,18-octaethylporphinato(1-methylimidazole)-cobalt(II). A model for deoxycoboglobin. J Am Chem Soc. 1974 Jul 10;96(14):4452–4463. doi: 10.1021/ja00821a018. [DOI] [PubMed] [Google Scholar]
  16. Maines M. D., Kappas A. The degradative effects of porphyrins and heme compounds on components of the microsomal mixed function oxidase system. J Biol Chem. 1975 Mar 25;250(6):2363–2369. [PubMed] [Google Scholar]
  17. Molinaro F. S., Little R. G., Ibers J. A. Oxygen binding to a model for the active site in cobalt-substituted hemoglobin. J Am Chem Soc. 1977 Aug 17;99(17):5628–5632. doi: 10.1021/ja00459a016. [DOI] [PubMed] [Google Scholar]
  18. Momenteau M., Rougée M., Loock B. Five-coordinate iron-porphyrin as a model for the active site of hemoproteins. Characterization and coordination properties. Eur J Biochem. 1976 Dec;71(1):63–76. doi: 10.1111/j.1432-1033.1976.tb11090.x. [DOI] [PubMed] [Google Scholar]
  19. Noll L., Barisas B. G., Gill S. J. Calorimetric measurement of stepwise enthalpy changes for the binding of four oxygens to adult human hemoglobin. Biochem Biophys Res Commun. 1974 Feb 4;56(3):555–560. doi: 10.1016/0006-291x(74)90639-1. [DOI] [PubMed] [Google Scholar]
  20. Perutz M. F. Structure and mechanism of haemoglobin. Br Med Bull. 1976 Sep;32(3):195–208. doi: 10.1093/oxfordjournals.bmb.a071363. [DOI] [PubMed] [Google Scholar]
  21. Roughton F. J. The oxygen equilibrium of mammalian hemoglobin. Some old and new physicochemical studies. J Gen Physiol. 1965 Sep;49(1 Suppl):105–126. doi: 10.1085/jgp.49.1.105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Spilburg C. A., Hoffman B. M., Petering D. H. Coboglobins. Influence of the apoprotein on oxygen binding to cobaltomyoglobin. J Biol Chem. 1972 Jul 10;247(13):4219–4223. [PubMed] [Google Scholar]
  23. Stynes H. C., Ibers J. A. Thermodyanamics of the reversible oxygenation of amine complexes of cobalt(II) protoporphyrin IX dimethyl ester in a nonagueous medium. J Am Chem Soc. 1972 Mar 8;94(5):1559–1562. doi: 10.1021/ja00760a021. [DOI] [PubMed] [Google Scholar]
  24. Tomita M., Irie M., Ukita T. Sensitized photooxidation of histidine and its derivatives. Products and mechanism of the reaction. Biochemistry. 1969 Dec;8(12):5149–5160. doi: 10.1021/bi00840a069. [DOI] [PubMed] [Google Scholar]
  25. Tyuma I., Shimizu K., Imai K. Effect of 2,3-diphosphoglycerate on the cooperativity in oxygen binding of human adult hemoglobin. Biochem Biophys Res Commun. 1971 Apr 16;43(2):423–428. doi: 10.1016/0006-291x(71)90770-4. [DOI] [PubMed] [Google Scholar]
  26. Wagner G. C., Kassner R. J. Spectroscopic properties of ferrous heme complexes of sterically hindered ligands. Biochim Biophys Acta. 1975 Jun 12;392(2):319–327. doi: 10.1016/0304-4165(75)90013-6. [DOI] [PubMed] [Google Scholar]
  27. Walker F. A. Reactions of monomeric cobalt-oxygen complexes. I. Thermodynamics of reaction of molecular oxygen with five- and six-coordinate amine complexes of a cobalt porphyrin. J Am Chem Soc. 1973 Feb 21;95(4):1154–1159. doi: 10.1021/ja00785a026. [DOI] [PubMed] [Google Scholar]
  28. Walker F. A. Steric and electronic effects in the coordination of amines to a cobalt(II) porphyrin. J Am Chem Soc. 1973 Feb 21;95(4):1150–1153. doi: 10.1021/ja00785a025. [DOI] [PubMed] [Google Scholar]
  29. Warshel A. Energy-structure correlation in metalloporphyrins and the control of oxygen binding by hemoglobin. Proc Natl Acad Sci U S A. 1977 May;74(5):1789–1793. doi: 10.1073/pnas.74.5.1789. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Yonetani T., Yamamoto H., Woodrow G. V., 3rd Studies on cobalt myoglobins and hemoglobins. I. Preparation and optical properties of myoglobins and hemoglobins containing cobalt proto-, meso-, and deuteroporphyrins and thermodynamic characterization of their reversible oxygenation. J Biol Chem. 1974 Feb 10;249(3):682–690. [PubMed] [Google Scholar]

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