The solid and solution state conformation of yunnanin A, a cyclic hept
apeptide, cyclo(-Gly-Tyr-Gly-Gly-Pro-Phe-Pro-),: isolated from the roo
ts of Stellaria yunnanensis were studied. The X-ray diffraction studie
s showed that the crystal of yunnanin A [orthorhombic form from a etha
nol-methanol mixture, a=11.754 (to), b=12.576 (7), c=30.731 (6) Angstr
om, space group P222(1), z=4] had three intramolecular hydrogen bonds
forming one type II, one type II' beta-turns, and a classical beta-bul
ge unit with all trans amide bonds. The dominant solution conformation
analyzed by NMR spectroscopy, Monte Carlo (MC) and restrained molecul
ar dynamics (MD) calculations implemented in MacroModel/Batchmin (Ver.
4.5) was homologous to that in the solid state. (C) 1997, Elsevier Sc
ience Ltd.