Skip to main content
PMC home page
Biophysical Journal logoLink to Biophysical Journal
. 1980 Oct;32(1):65–75. doi: 10.1016/S0006-3495(80)84916-2

Electrostatic stabilization in sperm whale and harbor seal myoglobins. Identification of groups primarily responsible for changes in anchoring of the A helix.

F R Gurd, S H Friend, T M Rothgeb, R S Gurd, H Scouloudi
PMCID: PMC1327257  PMID: 7248465

Abstract

The compact, largely helical structure of sperm whale and harbor seal myoglobins undergoes an abrupt one-step transition between pH 4.5 and 3.5 as monitored by changes in either the heme Soret band absorbance or circular dichroism probes of secondary structure, for which a modified Tanford-Kirkwood theory provides identification of certain dominant electrostatic interactions responsible for the loss of stability. A similar treatment permits identification of the electrostatic interactions primarily responsible for a process in which the anchoring of the A helix to other parts of the molecule is weakened. This process is detected with both myoglobins, in a pH range approximately 1 unit higher than the onset of the overall unfolding process, through changes in the circular dichroic spectra near 295 nm which correspond to the L1 O-O band of the only two tryptophan residues in these proteins, residues 7 and 14. In each case protonation of certain sites in neighboring parts of the molecule can be identified as producing destabilizing interactions with components of the A helix, particularly with lysine 6.

Full text

PDF
69

Selected References

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

  1. Acampora G., Hermans J., Jr Reversible denaturation of sperm whale myoglobin. I. Dependence on temperature, pH, and composition. J Am Chem Soc. 1967 Mar 29;89(7):1543–1547. doi: 10.1021/ja00983a001. [DOI] [PubMed] [Google Scholar]
  2. BRESLOW E., GURD F. R. Reactivity of sperm whale metmyoglobin towards hydrogen ions and p-nitrophenyl acetate. J Biol Chem. 1962 Feb;237:371–381. [PubMed] [Google Scholar]
  3. Botelho L. H., Friend S. H., Matthew J. B., Lehman L. D., Hanania G. I., Gurd F. R. Proton nuclear magnetic resonance study of histidine ionizations in myoglobins of various species. Comparison of observed and computed pK values. Biochemistry. 1978 Nov 28;17(24):5197–5205. doi: 10.1021/bi00617a020. [DOI] [PubMed] [Google Scholar]
  4. Bradshaw R. A., Gurd F. R. Comparison of myoglobins from harbor seal, porpoise, and sperm whale. V. The complete amino acid sequences of harbon seal and porpoise myoglobins. J Biol Chem. 1969 Apr 25;244(8):2167–2181. [PubMed] [Google Scholar]
  5. Frauenfelder H., Petsko G. A., Tsernoglou D. Temperature-dependent X-ray diffraction as a probe of protein structural dynamics. Nature. 1979 Aug 16;280(5723):558–563. doi: 10.1038/280558a0. [DOI] [PubMed] [Google Scholar]
  6. Friend S. H., Gurd F. R. Electrostatic stabilization in myoglobin. Interactive free energies between individual sites. Biochemistry. 1979 Oct 16;18(21):4620–4630. doi: 10.1021/bi00588a024. [DOI] [PubMed] [Google Scholar]
  7. Friend S. H., Gurd F. R. Electrostatic stabilization in myoglobin. pH dependence of summed electrostatic contributions. Biochemistry. 1979 Oct 16;18(21):4612–4619. doi: 10.1021/bi00588a023. [DOI] [PubMed] [Google Scholar]
  8. Gurd F. R., Rothgeb T. M. Motions in proteins. Adv Protein Chem. 1979;33:73–165. doi: 10.1016/s0065-3233(08)60459-3. [DOI] [PubMed] [Google Scholar]
  9. Hartzell C. R., Bradshaw R. A., Hapner K. D., Gurd F. R. Comparison of myoglobins from harbor seal, porpoise, and sperm whale. II. Reactivity toward hydrogen ion and cupric ion. J Biol Chem. 1968 Feb 25;243(4):690–696. [PubMed] [Google Scholar]
  10. Hermans J., Jr, Acampora G. Reversible denaturation of sperm whale myoglobin. II. Thermodynamic analysis. J Am Chem Soc. 1967 Mar 29;89(7):1547–1552. doi: 10.1021/ja00983a002. [DOI] [PubMed] [Google Scholar]
  11. Lee B., Richards F. M. The interpretation of protein structures: estimation of static accessibility. J Mol Biol. 1971 Feb 14;55(3):379–400. doi: 10.1016/0022-2836(71)90324-x. [DOI] [PubMed] [Google Scholar]
  12. Matthew J. B., Friend S. H., Botelho L. H., Lehman L. D., Hanania G. I., Gurd F. R. Discrete charge calculations of potentiometric titrations for globular proteins: sperm whale myoglobin, hemoglobin alpha chain, cytochrome c. Biochem Biophys Res Commun. 1978 Mar 30;81(2):416–421. doi: 10.1016/0006-291x(78)91549-8. [DOI] [PubMed] [Google Scholar]
  13. Matthew J. B., Hanania G. I., Gurd F. R. Electrostatic effects in hemoglobin: Bohr effect and ionic strength dependence of individual groups. Biochemistry. 1979 May 15;18(10):1928–1936. doi: 10.1021/bi00577a012. [DOI] [PubMed] [Google Scholar]
  14. Matthew J. B., Hanania G. I., Gurd F. R. Electrostatic effects in hemoglobin: hydrogen ion equilibria in human deoxy- and oxyhemoglobin A. Biochemistry. 1979 May 15;18(10):1919–1928. doi: 10.1021/bi00577a011. [DOI] [PubMed] [Google Scholar]
  15. Matthew J. B., Hanania G. I., Gurd F. R. Solvent accessibility calculations for sperm whale ferrimyoglobin based on refined crystallographic data. Biochem Biophys Res Commun. 1978 Mar 30;81(2):410–415. doi: 10.1016/0006-291x(78)91548-6. [DOI] [PubMed] [Google Scholar]
  16. Nigen A. M., Gurd F. R. Comparison of carboxymethylation patterns of harbor seal and sperm whale myoglobins. J Biol Chem. 1973 May 25;248(10):3708–3715. [PubMed] [Google Scholar]
  17. Pittsyn O. B. Invariant features of globin primary structure and coding of their secondary structure. J Mol Biol. 1974 Sep 15;88(2):287–300. doi: 10.1016/0022-2836(74)90482-3. [DOI] [PubMed] [Google Scholar]
  18. Richards F. M. Areas, volumes, packing and protein structure. Annu Rev Biophys Bioeng. 1977;6:151–176. doi: 10.1146/annurev.bb.06.060177.001055. [DOI] [PubMed] [Google Scholar]
  19. Richmond T. J., Richards F. M. Packing of alpha-helices: geometrical constraints and contact areas. J Mol Biol. 1978 Mar 15;119(4):537–555. doi: 10.1016/0022-2836(78)90201-2. [DOI] [PubMed] [Google Scholar]
  20. Scouloudi H. A preliminary comparison of metmyoglobin molecules from seal and sperm whale. J Mol Biol. 1978 Dec 25;126(4):661–671. doi: 10.1016/0022-2836(78)90014-1. [DOI] [PubMed] [Google Scholar]
  21. Scouloudi H., Baker E. N. X-ray crystallographic studies of seal myoglobin. The molecule at 2.5 A resolution. J Mol Biol. 1978 Dec 25;126(4):637–660. doi: 10.1016/0022-2836(78)90013-x. [DOI] [PubMed] [Google Scholar]
  22. Shire S. J., Hanania G. I., Gurd F. R. Electrostatic effects in myoglobin. Application of the modified Tanford-Kirkwood theory to myoglobins from horse, California grey whale, harbor seal, and California sea lion. Biochemistry. 1975 Apr 8;14(7):1352–1358. doi: 10.1021/bi00678a002. [DOI] [PubMed] [Google Scholar]
  23. Shire S. J., Hanania G. I., Gurd F. R. Electrostatic effects in myoglobin. Hydrogen ion equilibria in sperm whale ferrimyoglobin. Biochemistry. 1974 Jul 2;13(14):2967–2974. doi: 10.1021/bi00711a028. [DOI] [PubMed] [Google Scholar]
  24. Shire S. J., Hanania G. I., Gurd F. R. Electrostatic effects in myoglobin. pH and ionic strength variations of ionization equilibria for individual groups in sperm whale ferrimyoglobin. Biochemistry. 1974 Jul 2;13(14):2974–2979. doi: 10.1021/bi00711a029. [DOI] [PubMed] [Google Scholar]
  25. Strickland E. H. Aromatic contributions to circular dichroism spectra of proteins. CRC Crit Rev Biochem. 1974 Jan;2(1):113–175. doi: 10.3109/10409237409105445. [DOI] [PubMed] [Google Scholar]
  26. Strickland E. H., Horwitz J., Billups C. Fine structure in the near-ultraviolet circular dichroism and absorption spectra of tryptophan derivatives and chymotrypsinogen A at 77 degrees K. Biochemistry. 1969 Aug;8(8):3205–3213. doi: 10.1021/bi00836a012. [DOI] [PubMed] [Google Scholar]
  27. Takano T. Structure of myoglobin refined at 2-0 A resolution. I. Crystallographic refinement of metmyoglobin from sperm whale. J Mol Biol. 1977 Mar 5;110(3):537–568. doi: 10.1016/s0022-2836(77)80111-3. [DOI] [PubMed] [Google Scholar]
  28. Tanford C., Roxby R. Interpretation of protein titration curves. Application to lysozyme. Biochemistry. 1972 May 23;11(11):2192–2198. doi: 10.1021/bi00761a029. [DOI] [PubMed] [Google Scholar]
  29. Wittebort R. J., Rothgeb T. M., Szabo A., Gurd F. R. Aliphatic groups of sperm whale myoglobin: 13C NMR study. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1059–1063. doi: 10.1073/pnas.76.3.1059. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES