A propagating ATPase gradient drives transport of surface-confined cellular cargo.
A propagating ATPase gradient drives transport of surface-confined cellular cargo.
复制标题
传播的 ATP 酶梯度驱动表面限制的细胞货物的运输。
DOI：
10.1073/pnas.1401025111
复制
发表时间：
2014
影响因子：
11.1
通讯作者：
Mizuuchi,Kiyoshi
中科院分区：
文献类型：
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作者：
Vecchiarelli,AnthonyG;Neuman,KeirC;Mizuuchi,Kiyoshi
将复制的遗传物质忠实地分离到子细胞中对所有生物体都至关重要。在许多细菌中，染色体的分离涉及“着丝粒样”位点在染色体主体（类核）上的转运，这是由两种蛋白质分配系统介导的：一种非特异性DNA结合ATP酶（帕拉）和一种ATP酶刺激剂（ParB），它与着丝粒样位点结合。这些系统以前曾被提出通过一种基于顺应性的机制发挥作用，类似于基于肌动蛋白或微管的运动。在这里，我们重建的F-质粒分区系统使用的DNA地毯的流动池作为人工类核表面和磁珠涂有质粒分区复合物作为表面限制的货物。这个最小的系统概括了由与货物一起传播的表面ATP酶梯度驱动的定向货物运动。的动力学是一致的扩散棘轮模型，其中货物动态地建立，并与ATP酶的浓度梯度相互作用。化学电泳力随着货物不断地追逐ATP酶梯度而增强，允许货物基本上在ATP酶的连续行波上“冲浪”类核。在生物学背景下证明这种基于非细丝的运动机制建立了用于运输和定位大细胞货物的独特的一类运动系统。
The faithful segregation of duplicated genetic material into daughter cells is critical to all organisms. In many bacteria, the segregation of chromosomes involves transport of “centromere-like” loci over the main body of the chromosome, the nucleoid, mediated by a two-protein partition system: a nonspecific DNA-binding ATPase, ParA, and an ATPase stimulator, ParB, which binds to the centromere-like loci. These systems have previously been proposed to function through a filament-based mechanism, analogous to actin- or microtubule-based movement. Here, we reconstituted the F-plasmid partition system using a DNA-carpeted flow cell as an artificial nucleoid surface and magnetic beads coated with plasmid partition complexes as surface-confined cargo. This minimal system recapitulated directed cargo motion driven by a surface ATPase gradient that propagated with the cargo. The dynamics are consistent with a diffusion-ratchet model, whereby the cargo dynamically establishes, and interacts with, a concentration gradient of the ATPase. A chemophoresis force ensues as the cargo perpetually chases the ATPase gradient, allowing the cargo to essentially “surf” the nucleoid on a continuously traveling wave of the ATPase. Demonstration of this non–filament-based motility mechanism in a biological context establishes a distinct class of motor system used for the transport and positioning of large cellular cargo.