Tubulin Double Helix: Lateral and Longitudinal Curvature Changes of Tubulin Protofilament
Tubulin Double Helix: Lateral and Longitudinal Curvature Changes of Tubulin Protofilament
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微管蛋白双螺旋：微管蛋白原丝的横向和纵向曲率变化
DOI：
10.1002/smll.202001240
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发表时间：
2020
期刊：
影响因子：
13.3
通讯作者：
Safinya, Cyrus R.
中科院分区：
文献类型：
--
作者：
Lee, Juncheol;Song, Chaeyeon;Lee, Jimin;Miller, Herbert P.;Cho, Hasaeam;Gim, Bopil;Li, Youli;Feinstein, Stuart C.;Wilson, Leslie;Safinya, Cyrus R.
由于它们的天然结构，微管蛋白二聚体是蛋白质的构建块，可以自然地预先编程组装成微管（mt），微管是细胞骨架聚合物。在这里，通过纵向和横向的微管原丝的构象变化证明了多阳离子定向（即静电可调）的微管组装，形成了微管双螺旋和各种管状结构。同步加速器小角度X射线散射和透射电子显微镜揭示了一系列显著的纳米级组装结构：单层和双层双螺旋微管。从mt到新组装体的相变取决于聚合体的大小和浓度。决定观察相数量的两个特征尺度是与微管蛋白大小（≈4 nm）和MT直径（≈25 nm）相比的多阳离子大小。这项工作表明，使用具有剪刀和胶样性质的聚阳离子来实现蛋白质纳米管的“可编程分解”，将mt撕裂成双链微管并构建以前未发现的纳米结构的可行性。重要的是，微管的新角色被定义为超分子结构的二维形状可控构建块。这些发现为基于蛋白质的功能材料的设计提供了见解，例如，作为纳米级电子器件的金属化模板，分子螺钉和药物输送载体。
By virtue of their native structures, tubulin dimers are protein building blocks that are naturally preprogrammed to assemble into microtubules (MTs), which are cytoskeletal polymers. Here, polycation‐directed (i.e., electrostatically tunable) assembly of tubulins is demonstrated by conformational changes to the tubulin protofilament in longitudinal and lateral directions, creating tubulin double helices and various tubular architectures. Synchrotron small‐angle X‐ray scattering and transmission electron microscopy reveal a remarkable range of nanoscale assembly structures: single‐ and double‐layered double‐helix tubulin tubules. The phase transitions from MTs to the new assemblies are dependent on the size and concentration of polycations. Two characteristic scales that determine the number of observed phases are the size of polycation compared to the size of tubulin (≈4 nm) and to MT diameter (≈25 nm). This work suggests the feasibility of using polycations that have scissor‐ and glue‐like properties to achieve “programmable breakdown” of protein nanotubes, tearing MTs into double‐stranded tubulins and building up previously undiscovered nanostructures. Importantly, a new role of tubulins is defined as 2D shape‐controllable building blocks for supramolecular architectures. These findings provide insight into the design of protein‐based functional materials, for example, as metallization templates for nanoscale electronic devices, molecular screws, and drug delivery vehicles.