Abstract
X-Ray structure studies of poly(L-valine), poly(L-isoleucine), and poly(L-phenylalanine) have been carried out. Poly(L-valine) has two structural forms. One is an α-helical conformation packed in the hexagonal lattice with a dimension of a=11.43 Å, though this conformation is unfavorable for poly(L-valine). The other is a β pleated sheet structure with the crystal data: P212121, a=4.80 Å, b=19.14 Å, c=6.59 Å (fiber axis). The β poly(L-valine) gave an X-ray fiber photograph of high quality and a detailed structural study was carried out. Poly(L-isoleucine) also crystallizes in a β pleated sheet structure with a=4.8 Å, b=23 Å, c=6.6 Å, orthorhombic. Contraction of fiber axes in both β structures are observed. The X-ray fiber photograph of poly(L-phenylalanine) suggests the coexistence of ω- and α-helix. This specimen may be the third example of an ω-helix. The significance of the hydrophobic interaction of the side chains in the structures is discussed.
Similar content being viewed by others
Article PDF
References
S. Arnott, S. D. Dover, and A. Elliott, J. Mol. Biol., 30, 201 (1967).
V. Sasisekharan, Acta Crystallogr., 12, 897 (1959).
S. Yamashita and T. Yamashita, Proc. Natl. Acad. Sci., U.S.A., 72, 941 (1975).
E. R. Blout, C. De Lozé, S. M. Bloom, and G. D. Fasman, J. Am. Chem. Soc., 82, 3787 (1960).
S. Arnott, Polymer, 6, 478 (1965).
S. Arnott and A. J. Wonacott, J. Mol. Biol., 21, 371 (1966).
C. H. Bamford, W. E. Hanby, and F. Happey, Proc. R. Soc. London, Ser. A, 205, 30 (1951).
L. Brown and I. F. Trotter, Trans. Faraday Soc., 52, 537 (1956).
L. Pauling and R. B. Corey, Proc. Natl. Acad. Sci., U.S.A., 39, 253 (1953).
T. Miyazawa, J. Polym. Sci., 55, 215 (1961).
E. M. Bradbury, L. Brown, A. R. Downie, A. Elliott, W. E. Hanby, and T. R. R. McDonald, Nature, 183, 1736 (1959).
E. M. Bradbury, L. Brown, A. R. Downie, A. Elliott, R. D. B. Fraser, and W. E. Hanby, J. Mol. Biol., 5, 230 (1962).
R. D. B. Fraser, T. P. MacRae, and I. W. Stapleton, Nature, 193, 573 (1962).
S. Yamashita and T. Yamashita, to be published.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Yamashita, O., Yamane, T., Ashida, T. et al. X-Ray Structural Studies of Some Poly(α-amino acid)s with Hydrophobic Side Chains: Poly(L-valine), Poly(L-isoleucine), and Poly(L-phenylalanine). Polym J 11, 763–774 (1979). https://doi.org/10.1295/polymj.11.763
Issue date:
DOI: https://doi.org/10.1295/polymj.11.763
