Ab initio structure determination of a peptide β-turn from powder X-ray diffraction data

Ab initio crystal structure determination of the peptide Piv-Pro-Gly-NHMe directly from powder X-ray diffraction data, using the genetic algorithm technique for structure solution, has allowed the complete structural characterization of the Type II beta -turn conformation and the intermolecular interactions in this structure, and highlights the opportunities that now exist for structure determination of peptide systems when single crystals appropriate for single crystal X-ray diffraction experiments cannot be prepared.