Abstract
Previous studies have implicated carboxyl groups, sulphhydryl groups and amino groups as the sites for calcium binding in elastin. In this study, the concept was investigated that neutral co-ordinating sites in elastin may also provide calcium binding sites. Calcium binding to elastin was increased upon solvent changes which also effected conformational changes in the protein. In methanol-H2O mixtures calcium binding appeared to be independent of changes in pH and ionic strength. Of ten ions tested (Ca2+, Co2+, Na+, Cu2+, Zn2+, Cr3+, Pb+2, K+, Rb+, and Mg2+), only calcium binding was significantly increased when methanol was added. It is proposed that neutral sites are important to the various relationships involving calcium and elastin and perhaps serve as nucleation centers in the calcification of the protein.
Résumé
Des études précédentes suggèrent la présence de groupements carboxyles, sulfhydriles et aminés dans les sites de liaison en calcium de l'élastine. La possibilité de l'existence de sites neutres de liaison en calcium au niveau de l'élastine a été étudiée dans ce travail. Une augmentation de la fixation du calcium au niveau de l'élastine est observée après des modifications de dissolution qui ont aussi provoqué des modifications de structure de la protéine. Dans des mélanges méthanol-H2O, les liaisons du calcium semblent indépendantes du pH et de la force ionique. Sur dix ions testés (Ca2+, CO2+, Na2+, Cu2+, Zn2+, Cr3+, Pb+2, K+, Rb+ et Mg2+) seule la liaison du calcium est nettement augmentée, lorsque le méthanol est ajouté. Il semble que les sites neutres sont importants pour les divers rapports entre calcium et élastine et servent, peut-être, comme centres de nucléation au cours de la calcification de la protéine.
Zusammenfassung
Vorgängige Studien haben die Bedeutung der Carboxyl-, Sulfhydryl- und Aminogruppen als Stellen der Calciumbindung im Elastin gezeigt. Die vorliegende Arbeit hatte zum Ziel, die Rolle der neutralen Koordinationsstellen im Elastin als mögliche Calcium-Bindungsseite abzuklären. Die Calciumbindindung an das Elastin wurde durch solche Lösungsmittelveränderungen erhöht, die auch gleichartige Verschiebungen im Proteinmolekül bewirkten. In Methanol-Wasser-Mischungen schien die Calciumbindung nicht von Veränderungen des pH oder der Ionenstärke abhängig zu sein. Von 10 Ionen, bei welchen die Bindung überprüft wurde, war einzig diejenige des Calciums signifikant erhöht, wenn Methanol zugesetzt wurde. Es wird vorgeschlagen, daß die neutralen Stellen für die verschiedenen Vorgänge, bei welchen Calcium und Elastin beteiligt sind, eine wichtige Rolle spielen und vielleicht für die Verkalkung der Proteine als Nukleationszentren in Frage kommen.
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References
Eisenstein, R., Ayer, J. P., Papajiannis, S., Hass, G. M., Hellis, H.: Mineral binding by human arterial elastic tissue. Lab. Invest.13, 1198–1204 (1964)
Foster, J. A., Bruenger, E., Gray, W. R., Sanberg, L. B.: Isolation and amino acid sequences of tropoelastin peptides. J. biol. Chem.248, 2876–2879 (1973)
Geddes, A. J., Parker, K. D., Atkins, E. D. T., Beighton, E.: “Cross-β” conformation in proteins. J. molec. Biol.32, 343–358 (1968).
Good, N. E., Winget, G. D., Winter, W., Connolly, T. N., Tzawa, S., Singh, R. M. M.: Hydrogen ion buffers for biological research. Biochem.5, 467–477 (1966)
Gotte, L., Stern, P., Elsden, D. F., Partridge, S. M.: The chemistry of connective tissue. Biochem. J.87, 344–351 (1963)
Greenfield, N., Fasman, G. D.: Computed circular dichroism spectra for the evaluation of protein conformation. Biochem.10, 4108–4116 (1969)
Hall, D. A.: The reaction between elastase and elastic tissue. Biochem. J.59, 459–465 (1955)
Kagan, H. M., Crombie, G. D., Jordan, R. E., Lewis, W., Franzblau, C.: Proteolysis of elastin-ligand complexes-Stimulation of elastase digestion of insoluble elastin by sodium dodecyl sulfate. Biochem.11, 3412–3418 (1972)
Mammi, M., Gotte, L., Pezzin, G.: Comparison of soluble and native elastin conformations by far-ultraviolet circular dichroism. Nature (Lond.)220, 371–372 (1968)
Lowry, O. H., Rosebrough, N. J., Farr, A. L., Randell, R. J.: Protein measurement with the Folin-phenol reagent. J. biol. Chem.193, 265–275 (1951)
Mayers, D. F., Urry, D. W.: Valinomycin-cation complex. Conformational energy aspects. J. Amer. chem. Soc.,94, 77–94 (1972)
Molinari-Tosatti, M. P., Gotte, L.: Some features of the binding of calcium ions to elastin. Calc. Tiss. Res.6, 329–334 (1971)
Molinari-Tosatti, M. P., Galzignan, L., Moret, V., Gotte, L.: Some features of the binding of calcium ions to elastin. Calc. Tiss. Res.,2, Suppl., 88 (1968)
Partridge, S. M., Davis, H. F.: Composition of the soluble proteins derived from elastin. Biochem. J.61, 21–30 (1955)
Ross, R.: The elastic fiber, a review. J. Histochem. Cytochem.21, 199–208 (1973)
Rucker, R. B., Goettlich-Riemann, W., Tom, K.: Properties of chick tropoelastin. Biochim. biophys. Acta (Amst.)317, 193–201 (1973)
Sanberg, L. B., Zeikus, R. D., Coltrain, I. M.: Tropoelastin purification from copper-deficient swine: A simplified method. Biochim. biophys. Acta (Amst.)236, 542–545 (1971)
Shiffman, E., Corcoran, B. A., Martin, G. R.: Role of complexed heavy metals in initiating mineralization of “elastin” and the precipitation of mineral from solution. Arch. Biochem. Biophys.115, 87–94 (1966)
Shiffman, E., Lavender, D. R., Miller, E. J., Corcoran, B. A.: Amino acids at the nucleating site in mineralizing tissue. Calc. Tiss. Res.3, 125–135 (1969)
Shiffman, E., Martin, G. R., Corcoran, B. A.: The role of matrix in aortic calcification. Arch. Biochem. Biophys.107, 284–291 (1964)
Sobel, A. E., Leibowitz, S., Eilberg, R. G., Lamy, F.: Nucleation by elastin. Nature (Lond.)211, 45–47 (1966)
Starcher, B., Urry, D.: Elastin coacervate as a matrix for calcification. Biochem. biophys. Res. Commun.53, 210–216 (1973)
Starcher, B. C., Saccomari, G., Urry, D. W.: Coocervation and ion-binding studies on aortic elastin. Biochim. biophys. Acta (Amst.)310, 481–486 (1973)
Urry, D. W.: Neutral sites for calcium ion binding to elastin and collagen: A charge neutralization theory for calcification and its relationship to atheroscherosis. Proc. nat. Acad. Sci. (Wash.)68, 810–814 (1971)
Urry, D. W.: A molecular theory of ion-conducting channels: a field-dependent transition between conducting and nonconducting conformations. Proc. nat. Acad. Sci. (Wash.)69, 1610–1614 (1972)
Urry, D. W., Cummingham, W. D., Osbnishi, T.: A neutral polypeptide-calcium ion complex. Biochim. biophys. Acta (Amst.)292, 853–857 (1973)
Urry, D. W., Krivacia, J. R., Haider, J.: Calcium ion effects of notable change in elastin conformation by interacting at neutral sites. Biochem. biophys. Res. Commun.43, 6–11 (1971)
Urry, D. W., Ohnishi, M.: In: Spectroscopic approaches to biomolecular conformation (D. W. Urry, ed.), p. 86–112. Chicago: American Medical Association Press 1970
Urry, D. W., Starcher, B., Partridge, S. M.: Coacervation of solubilized elastin effects a notable conformational change. Nature (Lond.)222, 795–796 (1969)
Weis-Fogh, T., Anderson, S. O.: New molecular model for the long-range elasticity of elastin. Nature (Lond.)227, 718–721 (1970)
Yu, S. Y., Blumenthal, H. T.: The calcification of elastic tissue. In: The connective tissue (B. M. Wagner and D. E. Smith, eds.), p. 17–49. Baltimore: Williams & Wilkens Co. 1967
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Supported by grants from the Nutrition Foundation, USPHS-NIH Grant #HL-15965-01, and the California Yolo-Sacramento Heart Association.
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Rucker, R.B., Ford, D., Riemann, W.G. et al. Additional evidence for the binding of calcium ions to elastin at neutral sites. Calc. Tis Res. 14, 317–325 (1974). https://doi.org/10.1007/BF02060306
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DOI: https://doi.org/10.1007/BF02060306