Letter | Published:

Sense of the Helix in Poly-L-tyrosine

Naturevolume 193pages681682 (1962) | Download Citation



THE anomalous rotatory dispersion curves for many synthetic poly-α-amino-acids in the helical conformation have been adequately interpreted by the equation proposed by Moffitt1. The constant, b0, in this equation has been used as a measure of helix content in polypeptides and proteins2. The sign of b0 has been taken to signify the sense of the helix1,3–6. A value of approximately − 630 has been found for the helical conformation of poly-L-glutamic acid1a, poly-γ-benzyl-L-glutamate1,4 and for poly-L-alanine7; the latter has been shown to exist as a right-handed helix8. The first reported positive b0 value was that found for poly-L-tyrosine7, and it was suggested that the unusual sign of b0 is a consequence of a strong chromophoric group near the β-carbon. Other positive b0 values have since been reported for poly-β-benzyl-L-aspartate3, poly-1-benzyl-L-histidine9 and poly-L-tryptophan10. It was suggested that the positive b0 value of poly-β-benzyl-L-aspartate was due to a different sense of twist3 than that found for poly-γ-benzyl-L-glutamate. Proof of this hypothesis followed shortly4,11.

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    (a) Moffitt, W., Proc. U.S. Nat Acad. Sci., 42, 736 (1956). (b) Moffitt, W., and Yang, J. T., ibid., 42, 596 (1956).

  2. 2

    (a) Cohen, C., and Szent-Györgyi, A., J. Amer. Chem. Soc., 79, 248 (1957). (b) Blout, E. R., and Idelson, M., ibid., 80, 4912 (1958). (c) Doty, P., Proc. Fourth Intern. Cong. Biochem., Vienna, 8 (Pergamon Press, London, 1959).

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    Blout, E. R., and Karlson, R. H., J. Amer. Chem. Soc., 80, 1259 (1958).

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    Karlson, R. H., Norland, K. S., Fasman, G. D., and Blout, E. R., J. Amer. Chem. Soc., 82, 2268 (1960).

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    (a) Fitts, D. D., and Kirkwood, J. G., Proc. U.S. Nat. Acad. Sci., 43, 1046 (1957). (b) Doty, P., and Yang, J. T., J. Amer. Chem. Soc., 78, 498 (1956).

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    (a) Yang, J. T., and Doty, P., J. Amer. Chem. Soc., 79, 761 (1957). (b) Doty, P., and Lundberg, R. D., Proc. U.S. Nat. Acad. Sci., 43, 213 (1957).

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    Elliott, A., Hanby, W. E., and Malcolm, B. R., Nature, 180, 1340 (1957).

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    Downie, A. R., Elliott, A., Hanby, W. A., and Malcolm, B. R., Proc. Roy. Soc., A, 242, 325 (1957).

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    Katchalski, E., Fasman, G. D., and Blout, E. R., Abst. Amer. Chem. Soc. Meeting, San Francisco, April 1958.

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    Sela, M., Steinberg, I. Z., and Daniel, E., Biochim. Biophys. Acta, 46, 433 (1961).

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    Bradbury, E. M., Downie, A. R., Elliott, A., and Hanby, W. E., Proc. Roy. Soc., A, 259, 110 (1960).

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    Downie, A. R., Elliott, A., and Hanby, W. E., Nature, 183, 110 (1959).

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    Coombes, J. D., Katchalski, E., and Doty, P., Nature, 185, 534 (1960).

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    Doty, P., Imahori, K., and Klemperer, E., Proc. U.S. Nat. Acad. Sci., 44, 424 (1958). Blout, E. R., and Idelson, M., J. Amer. Chem. Soc., 80, 4909 (1958).

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    Present address: Graduate Department of Biochemistry, Brandeis University, Waltham, 54, Mass.


  1. Children's Cancer Research Foundation, and the Harvard Medical School



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