摘要翻译：
研究了影响RNA折叠/去折叠动力学的光镊仪器实验变量。将一个模型RNA发夹P5ab通过RNA/DNA杂交手柄连接到两个微米大小的小珠上；一个珠被双束激光捕获，另一个被微移液管保持。在测量展开/再折叠动力学时，改变了几个实验变量，包括手柄长度、陷阱刚度和施加在分子上的力模式。在恒力模式下，通过反馈控制来维持施加在RNA上的张力，当手柄长度变化10倍(1.1～10.2Kbp)时，测得的速率系数变化幅度在40%以内；当陷阱刚度降低到三分之一(0.1～0.035pn/nm)时，它们增加了2～3倍。在被动模式下，没有反馈控制，施加在RNA上的力随系绳的端到端距离变化而变化，RNA在高作用力折叠状态和低作用力展开状态之间跳跃。在这种模式下，使用更长的手柄或更软的陷阱，速率增加了两倍。总的来说，在所研究的广泛条件下，测量的速率保持在相同的数量级。在论文（1）中，我们分析了所测得的动力学参数与RNA固有分子速率之间的差异，以及如何获得分子速率。
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英文标题：
《Force unfolding kinetics of RNA using optical tweezers. I. Effects of
  experimental variables on measured results》
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作者：
J.-D. Wen, M. Manosas, P. T. X. Li, S. B. Smith, C. Bustamante, F.
  Ritort, I. Tinoco Jr
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最新提交年份：
2007
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分类信息：

一级分类：Physics        物理学
二级分类：Biological Physics        生物物理学
分类描述：Molecular biophysics, cellular biophysics, neurological biophysics, membrane biophysics, single-molecule biophysics, ecological biophysics, quantum phenomena in biological systems (quantum biophysics), theoretical biophysics, molecular dynamics/modeling and simulation, game theory, biomechanics, bioinformatics, microorganisms, virology, evolution, biophysical methods.
分子生物物理、细胞生物物理、神经生物物理、膜生物物理、单分子生物物理、生态生物物理、生物系统中的量子现象（量子生物物理）、理论生物物理、分子动力学/建模与模拟、博弈论、生物力学、生物信息学、微生物、病毒学、进化论、生物物理方法。
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一级分类：Physics        物理学
二级分类：Soft Condensed Matter        软凝聚态物质
分类描述：Membranes, polymers, liquid crystals, glasses, colloids, granular matter
膜，聚合物，液晶，玻璃，胶体，颗粒物质
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一级分类：Physics        物理学
二级分类：Statistical Mechanics        统计力学
分类描述：Phase transitions, thermodynamics, field theory, non-equilibrium phenomena, renormalization group and scaling, integrable models, turbulence
相变，热力学，场论，非平衡现象，重整化群和标度，可积模型，湍流
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一级分类：Quantitative Biology        数量生物学
二级分类：Biomolecules        生物分子
分类描述：DNA, RNA, proteins, lipids, etc.; molecular structures and folding kinetics; molecular interactions; single-molecule manipulation.
DNA、RNA、蛋白质、脂类等；分子结构与折叠动力学；分子相互作用；单分子操作。
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英文摘要：
  Experimental variables of optical tweezers instrumentation that affect RNA folding/unfolding kinetics were investigated. A model RNA hairpin, P5ab, was attached to two micron-sized beads through hybrid RNA/DNA handles; one bead was trapped by dual-beam lasers and the other was held by a micropipette. Several experimental variables were changed while measuring the unfolding/refolding kinetics, including handle lengths, trap stiffness, and modes of force applied to the molecule. In constant-force mode where the tension applied to the RNA was maintained through feedback control, the measured rate coefficients varied within 40% when the handle lengths were changed by 10 fold (1.1 to 10.2 Kbp); they increased by two- to three-fold when the trap stiffness was lowered to one third (from 0.1 to 0.035 pN/nm). In the passive mode, without feedback control and where the force applied to the RNA varied in response to the end-to-end distance change of the tether, the RNA hopped between a high-force folded-state and a low-force unfolded-state. In this mode, the rates increased up to two-fold with longer handles or softer traps. Overall, the measured rates remained with the same order-of-magnitude over the wide range of conditions studied. In the companion paper (1), we analyze how the measured kinetics parameters differ from the intrinsic molecular rates of the RNA, and thus how to obtain the molecular rates.
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PDF链接：
https://arxiv.org/pdf/707.058