Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
Nucleic Acids Res. 2010 Dec;38(22):8284-94. doi: 10.1093/nar/gkq662. Epub 2010 Aug 6.
Agarose gel electrophoresis, circular dichroism and differential scanning calorimetry showed that single-stranded RNA from satellite tobacco mosaic virus transforms from a conformationally 'closed state' at 4°C to a more conformationally 'open state' at 65°C. The transition is reversible and shows no hysteresis. Atomic force microscopy (AFM) allowed visualization of the two states and indicated that the conformationally 'closed state' probably corresponds to the native encapsidated conformation, and that the 'open state' represents a conformation, characterized as short, thick chains of domains, as a consequence of the loss of tertiary interactions. Heating from 75°C to 85°C in the presence of EDTA was necessary to further unravel the 'open' conformation RNA into extended chains of lengths >280 nm. Virus exposed to low concentrations of phenol at 65°C, extruded RNA as distinctive 'pigtails' in a synchronous fashion, and these 'pigtails' then elongated, as the RNA was further discharged by the particles. Moderate concentrations of phenol at 65°C produced complete disruption of virions and only remains of decomposed particles and disordered RNA were evident. AFM images of RNA emerging from disrupted virions appear most consistent with linear arrangements of structural domains.
琼脂糖凝胶电泳、圆二色性和差示扫描量热法表明，卫星烟草花叶病毒的单链 RNA 从 4°C 的构象“封闭状态”转变为 65°C 的更构象“开放状态”。这种转变是可逆的，没有滞后现象。原子力显微镜（AFM）允许观察两种状态，并表明构象“封闭状态”可能对应于天然包裹的构象，而“开放状态”代表一种构象，其特征是短而粗的结构域链，这是由于丧失了三级相互作用的结果。在 EDTA 存在下从 75°C 加热到 85°C 是必要的，以进一步将“开放”构象 RNA 解开成长度大于 280nm 的延伸链。病毒在 65°C 下暴露于低浓度的苯酚时，以同步的方式将 RNA 挤出为独特的“辫子”，随着颗粒进一步排出 RNA，这些“辫子”会延长。65°C 时中等浓度的苯酚会导致病毒完全解体，只有分解颗粒和无序 RNA 的残留物是明显的。从破裂的病毒颗粒中出现的 RNA 的 AFM 图像似乎与结构域的线性排列最一致。
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