Cyclolinopeptide B methanol trisolvate

The title compound, C56H83N9O9S center dot 3CH(3)OH, is a methanol trisolvate of the cyclolinopeptide cyclo(Met(1)-Leu(2)-Ile(3)-Pro(4)-Pro(5)-Phe(6)-Phe(7)-Val(8)-Ile(9)) (henceforth referred to as CLP-B), which was isolated from flaxseed oil. All the amino acid residues are in an l-configuration based on the CORN rule. The cyclic nonapeptide exhibits eight trans peptide bonds and one cis peptide bond observed between the two proline residues. The conformation is stabilized by an alpha-turn and two consecutive beta-turns each containing a N-H center dot center dot center dot O hydrogen bond between the carbonyl group O atom of the first residue and the amide group H atom of the fourth (alpha-turn) or the third residue (beta-turns), repectively. In the crystal, the components of the structure are linked by N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds into chains parallel to the a axis.