Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
Nucleic Acids Res. 2012 Oct;40(19):e151. doi: 10.1093/nar/gks651. Epub 2012 Jul 5.
A molecular system of a nanometer-sized reel was developed from F(1)-ATPase, a rotary motor protein. By combination with magnetic tweezers and optical tweezers, single-molecule double-stranded DNA (dsDNA) was wound around the molecular reel. The bending stiffness of dsDNA was determined from the winding tension (0.9-6.0 pN) and the diameter of the wound loop (21.4-8.5 nm). Our results were in good agreement with the conventional worm-like chain model and a persistence length of 54 ± 9 nm was estimated. This molecular reel system offers a new platform for single-molecule study of micromechanics of sharply bent DNA molecules and is expected to be applicable to the elucidation of the molecular mechanism of DNA-associating proteins on sharply bent DNA strands.
从旋转马达蛋白 F(1)-ATP 酶中开发出纳米尺寸线轴的分子系统。通过与磁镊和光镊结合，将单链 DNA（dsDNA）缠绕在分子线轴上。从缠绕张力（0.9-6.0 pN）和缠绕环的直径（21.4-8.5 nm）确定 dsDNA 的弯曲刚度。我们的结果与传统的蠕虫状链模型吻合较好，估计出的刚性长度为 54 ± 9 nm。这种分子线轴系统为单分子研究急剧弯曲的 DNA 分子的微观力学提供了一个新的平台，有望应用于阐明 DNA 结合蛋白在急剧弯曲的 DNA 链上的分子机制。
