3-DIMENSIONAL RECONSTRUCTION OF THE 14-FILAMENT FIBERS OF HEMOGLOBIN-S
3-DIMENSIONAL RECONSTRUCTION OF THE 14-FILAMENT FIBERS OF HEMOGLOBIN-S
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DOI：
10.1016/0022-2836(79)90434-0
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发表时间：
1979-01-01
影响因子：
5.6
通讯作者：
EDELSTEIN, SJ
中科院分区：
文献类型：
--
作者：
DYKES, GW;CREPEAU, RH;EDELSTEIN, SJ
通过EM和基于计算机的图像重建研究了[人] S的超分子结构。通过镰状细胞的裂解或Hb S溶血产物的搅拌制备的负染色纤维几乎完全是20 nm直径的形式。这些纤维的直径在18 nm和23 nm的极值之间具有周期性变化。计算的傅立叶变换的纤维显示出一个高度复杂的模式的倒易空间最大值，与30个最大值的20层线清楚地解决。最大值的贝塞尔顺序分配的援助下，一个新开发的技术，结合实空间傅立叶空间重建方法（RE-FORM）。该方法利用低分辨率最大值的逆傅立叶变换产生的滤波图像在真实的空间中计算螺旋纤维的横截面。改革分析表明，纤维具有椭圆形横截面，由14根六边形排列的长丝组成，10根外长丝包围4根内长丝。在此横截面的基础上，所有的最大值的贝塞尔顺序被分配，允许通过傅里叶-贝塞尔合成的三维重建的计算。从这些重建细节的位置Hb S分子的每一个丝获得。血红蛋白S分子在相邻的细丝中交错排列，产生紧密堆积的螺旋结构。重构的纤维在不同阶段的拆卸揭示了一个稳定的中间体，含有10根长丝，其特征在于在2对特定的外部长丝的损失。还鉴定了在对应于母体结构的3个内部细丝和3个外部细丝的位置处仅具有6个细丝的部分分解的纤维。6-细丝结构似乎是由10-细丝结构通过损失2对特定细丝产生的。细丝对是稳定完整纤维的重要结构单元，这些细丝对中分子的取向可能与已知存在于Hb S晶体中的细丝对有关。
The supramolecular structure of [human] S was studied by EM and computer-based image reconstruction. Negatively stained fibers prepared by the lysis of sickled cells or the stirring of Hb S hemolysates were almost exclusively of the 20 nm diameter form. These fibers had a periodic variation in diameter between the extremes of 18 nm and 23 nm. Computed Fourier transforms of the fibers showed a highly complex pattern of reciprocal space maxima, with 30 maxima on 20 layer-lines clearly resolved. The Bessel orders of the maxima were assigned with the aid of a newly developed technique, a combined real-space Fourier-space reconstruction method (RE-FORM). This method utilized the filtered image produced by the inverse Fourier transform of the low-resolution maxima to calculate in real space the cross-section of a helical fiber. The REFORM analysis indicated that the fibers had an elliptical cross-section and were composed of 14 hexagonally packed filaments with 10 outer filaments surrounding 4 inner filaments. On the basis of this cross-section, the Bessel orders of all the maxima were assigned, permitting the calculation of 3-dimensional reconstructions by Fourier-Bessel synthesis. From these reconstructions details of the location of Hb S molecules of each filament were obtained. Hb S molecules were staggered in adjacent filaments to produce a closely packed helical structure. Reconstructions of fibers at various stages of disassembly revealed a stable intermediate containing 10 filaments which could be characterized in terms of the loss of 2 pairs of specific outer filaments. A partially disassembled fiber with only 6 filaments at positions corresponding to 3 inner and 3 outer filaments of the parent structure was also identified. The 6-filament structure appeared to be produced from the 10-filament structure by the loss of 2 specific pairs of filaments. Pairs of filaments are evidently significant structural units in the stabilization of the complete fibers, and the orientation of the molecules in these pairs may be related to the filament pairs known to occur in crystals of Hb S.