Kartha G, Aimoto S, Varughese K I
Int J Pept Protein Res. 1986 Feb;27(2):112-7. doi: 10.1111/j.1399-3011.1986.tb01799.x.
The crystal structure of cyclo(L-Pro-Gly)3 was solved using X-ray crystallographic techniques. The backbone of the peptide is asymmetric and is made up of five trans peptide units and one cis peptide. There is a hydrogen bonded water bridge that links the carbonyl oxygens, O1 and O4. The molecules exist as dimers in the crystal lattice. The two molecules of the dimer are related by crystallographic twofold symmetry and are linked by two N-H ... O hydrogen bonds. The crystals are trigonal, space group P3(2)12 with a = 11.379(3), c = 32.93(1) and z = 6. The structure was solved by multisolution methods and refined by least squares technique to an R of 0.083.
采用X射线晶体学技术解析了环（L-脯氨酸-甘氨酸）3的晶体结构。该肽的主链是不对称的，由五个反式肽单元和一个顺式肽组成。存在一个氢键连接的水桥，连接羰基氧O1和O4。分子在晶格中以二聚体形式存在。二聚体的两个分子通过晶体学二重对称性相关联，并通过两个N-H...O氢键相连。晶体为三方晶系，空间群P3(2)12，a = 11.379(3)，c = 32.93(1)，z = 6。该结构通过多解方法解析，并通过最小二乘法精修至R值为0.083。
