Tims Hannah S, Widom Jonathan
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208-3500, USA.
Methods. 2007 Mar;41(3):296-303. doi: 10.1016/j.ymeth.2007.01.001.
Macromolecular assemblies and machines undergo large-scale conformational changes as essential features of their normal function. Modern stopped-flow instrumentation and biotechnology combine to provide a powerful tool for characterizing the rates and natures of these conformational changes. Standard commercially available instruments provide extraordinary sensitivity and speed, allowing analysis of millisecond or longer timescale processes, with concentrations as low as a few nanomolar and volumes of just a few hundred microliters. One can now place specific dyes anywhere desired on a nucleic acid, and often on a protein as well. This ability allows the use of fluorescence resonance energy transfer experiments for detailed conformational analyses, even as the system is evolving rapidly over time following the initiation of a reaction. This approach is ideally suited for analysis of intrinsic properties of chromatin and of the machines that control chromatin assembly, disassembly, and function.
大分子组装体和机器会经历大规模的构象变化，这是它们正常功能的基本特征。现代停流仪器与生物技术相结合，为表征这些构象变化的速率和性质提供了一个强大的工具。标准的商用仪器具有非凡的灵敏度和速度，能够分析毫秒级或更长时间尺度的过程，浓度低至几纳摩尔，体积仅几百微升。现在可以将特定的染料置于核酸上任何想要的位置，通常也可以置于蛋白质上。这种能力使得荧光共振能量转移实验可用于详细的构象分析，即使在反应开始后系统随时间快速演变的情况下也是如此。这种方法非常适合分析染色质的内在特性以及控制染色质组装、拆卸和功能的机器。
