Helix propensities of basic amino acids increase with the length of the side-chain.

نویسندگان

  • S Padmanabhan
  • E J York
  • J M Stewart
  • R L Baldwin
چکیده

Helix formation in a 17-residue alanine-lysine peptide and analogous peptides with specific lysine --> X substitutions, where X is 2,3-diamino-L-propionic acid, 2, 4-diamino-L-butyric acid or L-ornithine, have been examined using circular dichroism measurements. The dependence of helix content on X, its position in the sequence, and the number of lysine --> X substitutions are reasonably well described by using the Lifson-Roig theory modified to include N-capping, without explicitly considering charge-helix dipole interactions. The helix propensities for these basic amino acids increase with the length of the side-chain in the rank order 2,3-diamino-L-propionic acid < 2,4-diamino-L-butyric acid < ornithine < lysine. This parallels the increase in helix propensities with side-chain length of other polar and charged amino acids.

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عنوان ژورنال:
  • Journal of molecular biology

دوره 257 3  شماره 

صفحات  -

تاریخ انتشار 1996