Langs D A, Grochulski P, Duax W L, Pletnev V Z, Ivanov V T
Medical Foundation of Buffalo, New York 14203.
Biopolymers. 1991 Mar;31(4):417-23. doi: 10.1002/bip.360310407.
The crystal structure of a synthetic analogue of valinomycin, cyclo[-(L-Val-L-Hyi-L-Val-D-Hyi)2-(D-Val-L-Hyi-L-Val-D -Hyi)-] ([L-Val1, L-Val5]meso-valinomycin), C60H102N6O18, has been determined. Crystals grown from petroleum ether are orthorhombic, space group P2(1)2(1)2(1), with cell parameters a = 16.41(1), b = 18.76(1), c = 25.86(1) A, and Z = 4. The atomic coordinates for nonhydrogen atoms, except those of terminal carbons on one side chain, were refined in the anisotropic thermal motion approximation. The coordinate parameters of the H atoms were incorporated into the structure factor calculations at geometrically expected positions. Values of the standard and weighted R factors after refinement are 0.074 and 0.083, respectively. The crystal structure of the molecule is asymmetric and adopts a conformation with four 4----1 type and one 6----1 type intramolecular hydrogen bonds between amide nitrogens and carbonyl oxygens. Valinomycin binds potassium more than 100 times strongly than the D,L stereoisomeric analogue, as a result of a different spatial orientation of potentially interacting carbonyl groups.
已确定缬氨霉素合成类似物环[-(L-缬氨酸-L-羟基异缬氨酸-L-缬氨酸-D-羟基异缬氨酸)₂-(D-缬氨酸-L-羟基异缬氨酸-L-缬氨酸-D-羟基异缬氨酸)-]（[L-缬氨酸₁,L-缬氨酸₅]内消旋缬氨霉素），C₆₀H₁₀₂N₆O₁₈的晶体结构。从石油醚中生长的晶体为正交晶系，空间群P2(1)2(1)2(1)，晶胞参数a = 16.41(1)，b = 18.76(1)，c = 25.86(1) Å，Z = 4。除一侧链末端碳的原子坐标外，非氢原子的原子坐标在各向异性热运动近似下进行了精修。H原子的坐标参数在几何预期位置纳入结构因子计算。精修后的标准R因子和加权R因子值分别为0.074和0.083。该分子的晶体结构不对称，酰胺氮和羰基氧之间形成了四个4----1型和一个6----1型分子内氢键的构象。由于潜在相互作用羰基的空间取向不同，缬氨霉素与钾的结合力比D,L立体异构类似物强100多倍。
