The stability and screw sense of the <i>α</i> -helix in poly- <i>β</i> -benzyl-L-aspartate

Abstract

Abstract A number of polymers and copolymers containing β-benzyl-L-aspartate has been prepared and their optical rotatory dispersion in a variety of solvents has been measured. The results of these measurements together with studies of infra-red spectra, X-ray diffraction patterns, deuteration rates and molecular models lead to the following conclusions. (i) The α-helical form of poly-β-benzyl-L-aspartate is considerably less stable relative to the solvated randomly coiled form than that of poly-γ-benzyl-L-glutamate. (ii) The left-handed α-helix of poly-β-benzyl-L-aspartate is more stable than the right-handed one. (iii) The difference in stability between the two senses of α-helix is much less in the case of poly-β-benzyl-L-aspartate than in that of poly-γ-benzyl-L-glutamate or poly-L-alanine.