线性肽的结构与构象。十四。叔丁氧羰基-L-丙氨酰甘氨酸一水合物的结构
Structure and conformation of linear peptides. XIV. Structure of tert-butyloxycarbonyl-L-alanylglycine monohydrate.
作者信息
Subramanian E, Sahayamary J J
机构信息
Department of Crystallography and Biophysics, University of Madras, India.
出版信息
Int J Pept Protein Res. 1993 Apr;41(4):319-22. doi: 10.1111/j.1399-3011.1993.tb00445.x.
The crystal structure of a dipeptide tert-butyloxycarbonyl-L-alanylglycine monohydrate (C10H18N2O5.H2O), molecular weight 264, has been determined. The crystals are monoclinic, space group P2(1), with a = 10.767(1), b = 6.317(1), c = 10.981(2)A, beta = 109.15(2) degrees, and Z = 2, Dc = 1.24 g cm-3. The structure was solved by direct methods and refined to a final R-index of 0.045 for 856 reflections (sin theta/lambda < 0.55 A-1) with I > 2 sigma. The N-terminus of the molecule blocked with the t-Boc group is uncharged and the C-terminus exists in an unionized state. The peptide unit is trans and shows slight deviations from planarity. (delta omega = 3.1 degrees). The peptide backbone is folded, with torsion angles of phi 1 = -76.0(5), psi 1 = 164.3(4), omega 1 = 176.9(5), phi 2 = 116.1(5), psi 21 = -2.8(7) and psi 22 = 177.8(4) degrees. The conformation about the urethane bond (C5-N1) is trans. The urethane group is essential planar. The conformation of the boc group is trans-trans.
已测定二肽叔丁氧羰基-L-丙氨酰甘氨酸一水合物（C10H18N2O5·H2O）的晶体结构，其分子量为264。晶体为单斜晶系，空间群P2(1)，a = 10.767(1)，b = 6.317(1)，c = 10.981(2)Å，β = 109.15(2)°，Z = 2，Dc = 1.24 g cm-3。结构通过直接法解析，并对856个反射（sinθ/λ < 0.55 Å-1，I > 2σ）进行精修，最终R因子为0.045。分子中被叔丁氧羰基（t-Boc）基团封闭的N端不带电荷，C端以未电离状态存在。肽单元为反式，且与平面有轻微偏差（δω = 3.1°）。肽主链呈折叠状，扭转角分别为φ1 = -76.0(5)，ψ1 = 164.3(4)，ω1 = 176.9(5)，φ2 = 116.1(5)，ψ21 = -2.8(7)和ψ22 = 177.8(4)°。氨基甲酸酯键（C5-N1）的构象为反式。氨基甲酸酯基团基本呈平面状。叔丁氧羰基（boc）基团的构象为反-反式。
Zotero 插件