Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA. Electronic address: https://twitter.com/StephL_Johnson.
Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
J Mol Biol. 2022 Jul 30;434(14):167653. doi: 10.1016/j.jmb.2022.167653. Epub 2022 Jun 2.
ATP-dependent chromatin remodelers are essential enzymes that restructure eukaryotic genomes to enable all DNA-based processes. The diversity and complexity of these processes arethe complexity of the enzymes that carry them out, making remodelers a challenging class of molecular motors to study by conventional methods. Here we use a single molecule biophysical assay to overcome some of these challenges, enabling a detailed mechanistic dissection of a paradigmatic remodeler reaction, that of sliding a nucleosome towards the longer DNA linker. We focus on how two motors of a dimeric remodeler coordinate to accomplish such directional sliding. We find that ATP hydrolysis by both motors promotes coordination, suggesting a role for ATP in resolving the competition for directional commitment. Furthermore, we show an artificially constitutive dimer is no more or less coordinated, but is more processive, suggesting a cell could modulate a remodeler's oligomeric state to modulate local chromatin dynamics.
ATP 依赖的染色质重塑酶是至关重要的酶，它们重塑真核基因组，以实现所有基于 DNA 的过程。这些过程的多样性和复杂性使得进行这些过程的酶变得复杂，这使得重塑酶成为一类具有挑战性的分子马达，难以通过传统方法进行研究。在这里，我们使用单分子生物物理测定法来克服其中的一些挑战，从而能够对一个典范的重塑酶反应进行详细的机制剖析，即朝着较长的 DNA 连接子滑动核小体。我们专注于如何协调二聚体重塑酶的两个马达来完成这种定向滑动。我们发现两个马达的 ATP 水解都促进了协调，这表明 ATP 在解决定向承诺的竞争中发挥了作用。此外，我们还表明，人工组成的二聚体的协调性没有增加或减少，但具有更高的持续性，这表明细胞可以调节重塑酶的寡聚状态来调节局部染色质动力学。
