Structure of the fd DNA--gene 5 protein complex in solution. A neutron small-angle scattering study.
Structure of the fd DNA--gene 5 protein complex in solution. A neutron small-angle scattering study.
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溶液中 fd DNA-基因 5 蛋白复合物的结构。
DOI：
10.1016/0022-2836(81)90390-9
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发表时间：
1981
影响因子：
5.6
通讯作者：
Siegrist,H
中科院分区：
文献类型：
--
作者：
Torbet,J;Gray,DM;Gray,CW;Marvin,DA;Siegrist,H
用中子小角散射研究了FdDNA-gene 5蛋白复合体在溶液中的行为。结果如下：(1)单位长度的质量为1380或1610道尔顿/奥，这取决于是否假设一个基因5蛋白质分子分别与4个或5个核苷酸结合。这些值对应于7.9%或7.0%的轴向亚基重复数以及1.27或0.90μm的溶液中的总等高线长度。对于螺距为90？的螺旋，每转约有11至13个蛋白质。2.(2)在无限对比度下，复合体的横截面旋转半径为34.5µ3。(3)结构必须相当开放和溶解，如每亚单位的干体积、每单位长度的质量和旋转半径所示。在具有测量的旋转半径和单位长度的质量的均匀圆柱体中，每个亚单位所占的体积大约是复合体中测量的亚单位干体积的四倍。(4)从测量的旋转半径和辅助极大值的位置随对比的变化可以得出结论，DNA不可能位于螺旋结构的外周。这得到了DNA主干最大半径的计算支持。除了可能的DNA定位外，我们对溶液中复合体的结果与McPhersonet等人(1979b)提出的复杂结构模型一致。5.(5)体外重组形成的复合体在溶液结构上与从感染细胞分离的活体复合体没有本质区别。
Neutron small-angle scattering has been used to investigate the fd DNA-gene 5 protein complex in solution. Results are as follows.1.(1) The mass per unit length is found to be 1380 or 1610 daltons/Å, depending upon whether one gene 5 protein molecule is assumed to bind to four or five nucleotides, respectively. These values correspond to axial subunit repeats of 7.9 or 7.0 Å and to total contour lengths in solution of 1.27 or 0.90 μm. For a helix of pitch 90 Å there are between about 11 and 13 proteins per turn.2.(2) The cross-sectional radius of gyration at infinite contrast of the complex is 34.5 ± 1 Å.3.(3) The structure must be quite open and solvated as indicated by the dry volume per subunit, the mass per unit length, and the radius of gyration. The volume occupied per subunit in a uniform cylinder having the measured radius of gyration and mass per unit length is about four times greater than the measured subunit dry volume in the complex.4.(4) From the change with contrast of both the measured radius of gyration and the position of a subsidiary maximum we conclude that the DNA could not be on the outer periphery of the helical structure. This is supported by a calculation of the maximum radius of the DNA backbone. With the possible exception of the positioning of the DNA, our results for the complex in solution are in good agreement with a model proposed by McPhersonet al.(1979b) for the complex structure.5.(5) The complex formed by reconstitutionin vitrois not substantially different in its solution structure from thein vivocomplex isolated from infected cells.