The subunit positions within RNA polymerase holoenzyme determined by triangulation of centre-to-centre distances.
The subunit positions within RNA polymerase holoenzyme determined by triangulation of centre-to-centre distances.
复制标题
RNA 聚合酶全酶内的亚基位置由中心到中心距离的三角测量确定。
DOI：
10.1111/j.1432-1033.1980.tb07221.x
复制
发表时间：
1980
期刊：
影响因子：
--
通讯作者：
H. Crespi
中科院分区：
文献类型：
--
作者：
P. Stöckel;R. May;I. Strell;Z. Cejka;W. Hoppe;H. Heumann;W. Zillig;H. Crespi
多亚基酶DNA依赖性RNA聚合酶的完整“亚基中心结构”通过使用从散射差测量和相应的回转半径R计算的亚基间距离对亚基位置进行三角测量来确定。除了前文中提出的核心亚基α 2、β和β '之间的中心到中心距离d外，起始因子σ和α 2之间的d值（8.4 +/- 1.6 nm），β（4.4 +/- 2.2 nm）和β '（10.7 +/- 1.5 nm）来自σ的R（4.1 +/- 0.3 nm）和α 2-σ对全酶内的β-σ（6.1 +/-0.4 nm）、β-σ（5.6 +/-0.3 nm）和β ′-σ（7.5 +/-0.4 nm）（α 2 β β ′ σ）。中子小角散射测量使用不同的亚基（氘代），同位素混合物，散射长度密度匹配的“氢化”分子部分和延长曝光时间，因为弱散射效应标记的亚基内的分子复合物的结构参数是可访问的。与核心酶（α 2 β β '）结合的σ的整体形状被证明与最近通过X射线小角散射测量的孤立状态下的σ相同（在实验分辨率内）。孤立σ的精细形状被简化为椭圆体，该椭圆体相对于核心结构（α 2-β-β '）以“空间填充”的方式围绕通过三角测量获得的σ中心的位置定向。全酶的完整亚基排列显示在三维模型中。
The complete 'centre-of-subunit structure' of the multisubunit enzyme DNA-dependent RNA polymerase was determined by triangulation of the subunit positions using the intersubunit distances calculated from scattering difference measurements and from the corresponding radii of gyration R. In addition to the centre-to-centre distances d between the core subunits alpha 2, beta and beta' presented in the preceding paper, the values of d between initiation factor sigma and alpha 2 (8.4 +/- 1.6 nm), beta (4.4 +/- 2.2 nm) and beta' (10.7 +/- 1.5 nm) were derived from R of sigma (4.1 +/- 0.3 nm) in situ and of the pairs alpha 2--sigma (6.1 +/- 0.4 nm), beta--sigma (5.6 +/- 0.3 nm) and beta'--sigma (7.5 +/- 0.4 nm) within the holoenzyme (alpha 2 beta beta' sigma). The structural parameters of the subunits within their molecular complex are accessible for neutron small-angle scattering measurements using labelling of the different subunits (deuteration), total reconstitution of isotopic hybrids, scattering length density matching of 'hydrogenated' molecular parts and extended exposure times because of weak scattering effects. The overall shape of sigma bound to core enzyme (alpha 2 beta beta') proved to be identical (within experimental resolution) with sigma in the isolated state measured recently by X-ray small-angle scattering. The refined shape of isolated sigma was reduced to an ellipsoid which was orientated with respect to the core structure (alpha 2--beta--beta') in a 'space-filling' way around the position of the sigma centre obtained by triangulation. The complete subunit arrangement of holoenzyme is shown in a three-dimensional model.