ALPHA-HELIX STRUCTURE OF PARATHYROID-HORMONE FRAGMENT (1-34) PREDICTED BY MONTE-CARLO SIMULATED ANNEALING

Tertiary structure of parathyroid hormone fragment (1-34) is predicted by the Monto Carlo simulated annealing method. Among the 20 structure s obtained after completely unbiased calculations, the lowest-energy c onformation exhibits two a-helices around residues 2-10 and 18-22. Thi s structure agrees with the models, especially with the location of he lices, deduced from experiments. In addition, the simulation supports empirical implications in the following two points. (1) The helix near the N-terminus is more stable than the C-terminal one. (2) The rest o f the peptide segments are flexible and do not tend to have any defini te structure. Our calculation correctly predicts only an alpha-helix, whereas previous analyses by the Chou-Fasman method leave an ambiguity between an alpha-helix and a beta-strand. (C) Munksgaard 1993.