Wang Jiawei, Dauter Miroslawa, Alkire Randy, Joachimiak Andrzej, Dauter Zbigniew
SAIC-Frederick Inc., Basic Research Program, Argonne National Laboratory, Argonne, IL 60439, USA.
Acta Crystallogr D Biol Crystallogr. 2007 Dec;63(Pt 12):1254-68. doi: 10.1107/S0907444907054224. Epub 2007 Nov 16.
The crystal structure of triclinic hen egg-white lysozyme (HEWL) has been refined against diffraction data extending to 0.65 A resolution measured at 100 K using synchrotron radiation. Refinement with anisotropic displacement parameters and with the removal of stereochemical restraints for the well ordered parts of the structure converged with a conventional R factor of 8.39% and an R(free) of 9.52%. The use of full-matrix refinement provided an estimate of the variances in the derived parameters. In addition to the 129-residue protein, a total of 170 water molecules, nine nitrate ions, one acetate ion and three ethylene glycol molecules were located in the electron-density map. Eight sections of the main chain and many side chains were modeled with alternate conformations. The occupancies of the water sites were refined and this step is meaningful when assessed by use of the free R factor. A detailed description and comparison of the structure are made with reference to the previously reported triclinic HEWL structures refined at 0.925 A (at the low temperature of 120 K) and at 0.95 A resolution (at room temperature).
利用同步辐射在100 K下测得的分辨率为0.65 Å的衍射数据，对三斜晶系的鸡蛋清溶菌酶（HEWL）晶体结构进行了精修。采用各向异性位移参数并去除结构中有序部分的立体化学限制进行精修，最终传统R因子收敛于8.39%，自由R因子为9.52%。全矩阵精修给出了导出参数方差的估计值。除了129个残基的蛋白质外，在电子密度图中还定位了总共170个水分子、9个硝酸根离子、1个醋酸根离子和3个乙二醇分子。主链的8个片段和许多侧链采用了交替构象进行建模。对水位点的占有率进行了精修，通过自由R因子评估时这一步骤是有意义的。参照之前报道的在0.925 Å（在120 K低温下）和0.95 Å分辨率（在室温下）精修的三斜晶系HEWL结构，对该结构进行了详细描述和比较。
