Crystal structural studies of destripeptide (B28-B30) insulin

Single crystals of destripeptide (B28-B30) insulin (DTRI) in three forms were obtained by hanging-drop vapor diffusion method. Form 1 belongs to P21 space group with cell parameters a-4.77 nm, b=6.19 nm, c=6.12 nm, β=110.3°. Form 2 belongs to P4122 or P4322 space group with cell parameters a= 6.45 nm, c=12.07 nm. Form 3 belongs to P212121 space group with cell parameters a=4.98 nm, b=5.16 nm, c=10.06 nm. The structure of form 1 crystal was determined by molecular replacement method and refined at 0.23 nm resolution. The R-factor of the final model is 18.8% with r.m.s. deviations of 0.001 5 nm and 3.3?for the bond lengths and the bond angles, respectively. Studies on the crystal structure show that the removal of B28 Pro has brought DTRI structural changes which made it dissociate more easily than native insulin although DTRI can still form a hexamer.     

硝酸镧与大环聚醚l,8-萘并-16-冠-5络合物的分子和晶体的结构

硝酸镧与大环聚醚1,8-萘并-16-冠-5络合物晶体属单斜晶系,空间群P2₁/n,晶胞中含四个分子,晶胞参数a=15.455Å,b=11.512Å,c=13.825Å,β=109.6°.强度数据由PW-1100四圆衍射仪收集,采用CuK_a辐射.结构用重原子法求解,并用全矩阵最小二乘法对全部原子的坐标参数及其各向同性温度因子进行了修,最后的R因子为0.108.镧离子的配位数为11,其中5个醚氧在镧离子的一侧,La-O键长2.59～2.78Å,而三个双齿配位硝酸根中的6个氧在另一侧,La-O键长2.59～2.63Å.