title: Crystal structure and conformation of the cyclic tetramer of a repeat tripeptide of elastin, cyclo(L-valyl-L-prolylglycyl)4.
abstract: X-ray diffraction data were used to determine the crystal structure of cyclo-(L-Val-L-Pro-Gly)4, the cyclic tetramer of a repeat tripeptide of elastin. The crystals are monoclinic, space group C2, with a = 29.639(3), b = 7.099(1), c = 20.325 (2) A, and beta = 130.4(4) degrees. The structure was solved by direct methods and refined by least squares to R = 0.082 for 2603 observed reflections. The cyclic dodecapeptide contains two beta (II) turns. Hydrophilic and hydrophobic channels that run parallel to the b axis are formed by the stacking of cyclic peptides on twofold axes.
mesh_terms: D000595:Amino Acid Sequence; D004549:Elastin; D008958:Models, Molecular; D010456:Peptides, Cyclic; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D010456:Peptides, Cyclic; D004549:Elastin; C045778:cyclo(valyl-prolylglycyl)4