Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-26T13:38:08.589Z Has data issue: false hasContentIssue false

Secondary structures in β-casein peptide 1–42: a two dimensional nuclear magnetic resonance study

Published online by Cambridge University Press:  01 June 2009

N. Magnus Wahlgren
Affiliation:
Department of Food Technology, University of Lund, PO Box 124, S-221 00 Lund, Sweden Department of Physical Chemistry 2, University of Lund, PO Box 124, S-221 00 Lund, Sweden
Petr Dejmek
Affiliation:
Department of Food Engineering, University of Lund, PO Box 124, S-221 00 Lund, Sweden
Torbjörn Drakenberg
Affiliation:
Department of Physical Chemistry 2, University of Lund, PO Box 124, S-221 00 Lund, Sweden Chemical Laboratory, The Technical Research Center of Finland, PO Box 204, SF-0 2151, Finland

Summary

Two dimensional NMR spectroscopy was used to study the structure of a peptide composed of the N-terminal 42 amino acid residues of β-casein. The peptide was obtained by enzymic cleavage using endoproteinase Asp-N. Complete sequence-specific 1H NMR assignment was performed for the peptide at three Ca2+ concentrations (0, 22 and 37 mM). The NMR results show that the peptide was highly flexible and adopted multiple conformations. No stable secondary structures were present; however, the peptide had some regions with non-random structure. The region between residues Leu16 and Asn27 adopted conformations with an increased contribution of α-helical structure, a so-called nascent helix. Two regions, Glu11-SerP15 and Lys29-Phe33 showed an increased population of conformations with extended structures. Addition of Ca2+ induced chemical shift changes for the backbone amide protons, especially around the phosphoserine region and around the suggested α-helical structure, indicating that the addition of Ca2+ stabilized the structure already present in the apo form of the peptide.

Type
Original articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1994

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Andrews, A. L., Atkinson, D., Evans, M. T. A., Finer, E. G., Green, J. P., Philips, M. C. & Robertson, R. N. 1979 The conformation and aggregation of bovine β-casein A. I. Molecular aspects of thermal aggregation. Biopolymers 18 11051121CrossRefGoogle Scholar
Bax, A. 1985 A spatially selective composite 90° radiofrequency pulse. Journal of Magnetic Resonance 65 142145Google Scholar
Billeter, M., Braun, W. & Wüthrich, K. 1982 Sequential resonance assignments in protein 1H nuclear magnetic resonance spectra. Computation of sterically allowed proton-proton distances and statistical analysis of proton-proton distances in single crystal protein conformations. Journal of Molecular Biology 155 321346CrossRefGoogle Scholar
Bouhallab, S., Léonil, J. & Maubois, J. L. 1991 [Study of β-casein phosphopeptide (l–25)-iron complex: action of alcalase and acid phosphatase.] Lait 71 435443CrossRefGoogle Scholar
Chaplin, L. C., Clark, D. C. & Smith, L. J. 1988 The secondary structure of peptides derived from caseins: a circular dichroism study. Biochimica et Biophysica Acta 956 162172CrossRefGoogle ScholarPubMed
Chazin, W. J. & Wright, P. E. 1987 A modified strategy for identification of 1H spin systems in proteins. Biopolymers 26 973977CrossRefGoogle ScholarPubMed
Creamer, L. K., Richardson, T. & Parry, D. A. D. 1981 Secondary structure of bovine αs1 and β-casein in solution. Archives of Biochemistry and Biophysics 211 689696CrossRefGoogle Scholar
Dickson, I. R. & Perkins, D. J. 1971 Studies on the interactions between purified bovine caseins and alkaline-earth metal ions. Biochemical Journal 124 235240CrossRefGoogle ScholarPubMed
Drapeau, G. R. 1980 Substrate specificity of a proteolytic enzyme isolated from a mutant of Pseudomonas fragi. Journal of Biological Chemistry 255 839840CrossRefGoogle ScholarPubMed
Dyson, H. J., Range, M., Houghten, R. A., Wright, P. E. & Lerner, R. A. 1988 Folding of immunogenic peptide fragments of proteins in water solution. II. The nascent helix. Journal of Molecular Biology 201 201217CrossRefGoogle ScholarPubMed
Dyson, H. J. & Wright, P. E. 1991 Defining solution conformations of small linear peptides. Annual Review of Biophysics and Biophysical Chemistry 20 519538CrossRefGoogle ScholarPubMed
Farrell, H. M. 1988 Physical equilibria: proteins. In Fundamentals of Dairy Chemistry, pp. 461510 (Eds Wong, N. P., Jenness, R., Keeney, M. and Marth, E. H.). New York: Van Nostrand ReinholdGoogle Scholar
Fox, P. F. & Guiney, J. 1972 A procedure for the partial fractionation of the αs-casein complex. Journal of Dairy Research 39 4953CrossRefGoogle Scholar
Graham, E. R. B., Malcolm, G. N. & McKenzie, H. A. 1984 On the isolation and conformation of bovine β-casein A1. International Journal of Biological Macromolecules 6 155161Google Scholar
Herskovits, T. T. 1966 On the conformation of caseins. Optical rotatory properties. Biochemistry 5 10181026Google Scholar
Holt, C. 1992 Structure and stability of bovine casein micelles. Advances in Protein Chemistry 43 63151CrossRefGoogle ScholarPubMed
Holt, C. & Sawyer, L. 1988 Primary and predicted secondary structures of the caseins in relation to their biological functions. Protein Engineering 2 251259CrossRefGoogle ScholarPubMed
Holt, C. & Sawyer, L. 1993 Caseins as rheomorphic proteins: interpretation of primary and secondary structures of the αs1-,β- and κ-caseins. Journal of the Chemical Society Faraday Transactions 89 26832692CrossRefGoogle Scholar
Kumosinski, T. F., Brown, E. M. & Farrell, H. M. 1991 Molecular modelling in food research: applications. Food Science and Technology 2 190195CrossRefGoogle Scholar
Kumosinski, T. F., Brown, E. M. & Farrell, H. M. 1993 a Three-dimensional molecular modeling of bovine caseins: an energy-minimized β-casein structure. Journal of Dairy Science 76 931945Google Scholar
Kumosinski, T. F., Brown, E. M. & Farhell, H. M. 1993 b Three-dimensional molecular modeling of bovine caseins: a refined, energy-minimized κ-casein structure. Journal of Dairy Science 76 25072520Google Scholar
Marion, D. & Wüthrich, K. 1983 Application of phase sensitive two-dimensional correlated spectroscopy (COSY) for measurements of 1H-1H spin-spin coupling constants in proteins. Biochemical and Biophysical Research Communications 113 967974CrossRefGoogle ScholarPubMed
Pardi, A., Wagner, G. & Wüthrich, K. 1983 Protein conformation and proton nuclear-magnetic-resonance chemical shifts. European Journal of Biochemistry 137 445454Google Scholar
Payens, T. A. J. & Van Markwijk, B. W. 1963 Some features of the association of β-casein. Biochimica et Biophysica Acta 71 517530Google Scholar
Rance, M. 1987 Improved methods for homonuclear rotating-frame and isotropic mixing experiments. Journal of Magnetic Resonance 74 557564Google Scholar
Rollema, H. S. 1992 Casein association and micelle formation. In Advanced Dairy Chemistry vol. 1, pp. 111140 (Ed. Fox, P. F.). London: Elsevier Applied ScienceGoogle Scholar
Schmidt, D. G. 1982 Association of caseins and casein micelle structure. In Developments in Dairy Chemistry—1. Proteins, pp. 6186 (Ed. Fox, P. F.). London: Applied Science Publishers.Google Scholar
Schmidt, D. G. & Payens, T. A. J. 1976 Micellar aspects of casein. Surface and Colloid Science 9 165229Google Scholar
Shaka, A. J., Lee, C. J. & Pines, A. 1988 Iterative schemes for bilinear operators. Journal of Magnetic Resonance 77 274293Google Scholar
States, D. J., Haberkorn, R. A. & Ruben, D. J. 1982 A two-dimensional nuclear overhauser experiment with pure absorption phase in four quadrants. Journal of Magnetic Resonance 48 286292Google Scholar
Wahlgren, N. M., Dejmek, P. & Drakenberg, T. 1993 a Binding of Mg2+ and Ca2+ to β-casein A1: a multi-nuclear magnetic resonance study. Journal of Dairy Research 60 6578CrossRefGoogle Scholar
Wahlgren, N. M., Leonil, J., Dejmek, P. & Drakenberg, T. 1993 b Two-dimensional nuclear magnetic resonance study of the β-casein peptide 1–25: resonance assignments and secondary structure. Biochimica et Biophysica Acta 1202 121128CrossRefGoogle ScholarPubMed