Ab initio structure determination of a peptide beta-turn from powder X-raydiffraction data

Ab initio crystal structure determination of the peptide Piv-Pro-Gly-NHMe d irectly from powder X-ray diffraction data, using the genetic algorithm tec hnique for structure solution, has allowed the complete structural characte rization of the Type II beta -turn conformation and the intermolecular inte ractions in this structure, and highlights the opportunities that now exist for structure determination of peptide systems when single crystals approp riate for single crystal X-ray diffraction experiments cannot be prepared.