Thermodynamics and Kinetics on the Folding Transition of Single Molecular Chain

单分子链折叠转变的热力学和动力学

• 批准号: 10206204
• 负责人: YOSHIKAWA Kenichi
• 金额: $ 14.72万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10206204/
• 关键词: Thermodynamical parameter; Coil - globule transition; Mesoscopic; Single molecular chain; Folding transition; Long DNA chain; Transition entropy; Condensation transition; 高分子鎖; マルチカノニカルモンテカルロシミュレーション; 単一分子観察; DNA; 相図; 凝縮構造

A great progress has been attained with our studies on the folding phase transition at the level of a single molecule both in theoretical and experimental approaches. In the theoretical approach, we have employed simulations of molecular dynamics incorporating Brownian motion and kinetic analyses on folding processes of a single molecule. As a result, it has become clear that ordered structures in nanometer scale are generated through the process of nucleation ＆ growth. It has also been indicated that the probability of the nuclear formation is a Poisson-like process and the growth is a time-linear process. It has also become clear that disordered spherical condensed structure is generated by spinodal decomposition in high degree of non-equilibrium. In the experimental approach, studies on transportation and structure regulation of a single polymer chain by use of infrared laser have been developed. Dielectric traps by YAG laser light beam at 1000 nm in wave length were performed with setting the focus within about 1 μm. Under such experimental conditions, chemicai degradation on DNA molecules is avoided. We showed that a long DNA molecule in compact structure formed through folding transition can be easily transported in solution without any chemical modification. We further found that the structure of a long DNA molecule is regulated without any mechanical treatment, by transporting the specimen to the solution with different chemical compositions. Our study provides the principle technology that leads to a LABORATORY for the μm-scaled microscopic chemistry and molecular biology.

我们对单分子水平折叠相变的研究在理论和实验上都取得了很大进展。在理论方法中，我们采用了结合布朗运动的分子动力学模拟和单个分子折叠过程的动力学分析。结果表明，纳米尺度的有序结构是通过成核和生长过程产生的。也有人指出，核形成的概率是类泊松过程，生长是时间线性过程。还清楚的是，无序球形凝聚结构是通过高度非平衡的旋节线分解产生的。在实验方法中，已经开展了利用红外激光对单个聚合物链的传输和结构调控的研究。将焦点设定在约1μm以内，利用波长1000nm的YAG激光束进行电介质陷阱。在这样的实验条件下，避免了DNA分子的化学降解。我们证明，通过折叠转变形成的结构紧凑的长DNA分子可以在溶液中轻松运输，无需任何化学修饰。我们进一步发现，通过将样本转移到具有不同化学成分的溶液中，无需任何机械处理即可调节长DNA分子的结构。我们的研究提供了建立微米级微观化学和分子生物学实验室的原理技术。

项目成果

V.A.Kabanov: "Interpolyelectrolyte Complexes Formed by DNA and Astramol Poly (propylene imine) Dendrimers"Macromolecules. 33. 9587-9593 (2000)

V.A.Kabanov：“由 DNA 和 Astramol 聚（丙烯亚胺）树枝状聚合物形成的聚电解质复合物”大分子。

I. Motoike: "Information Operations with an Excitable Field"Phys. Rev.. E59. 5354-5360 (1999)

I. Motoike：“具有兴奋场的信息操作”Phys。

D. Umeno: "Temperature-directed Compaction of Single DNA Molecule Grafted with Poly (N-isopropylacrylamide)"Nucleic Acids Symposium Serise. 39. 175-176 (1998)

D. Umeno：“聚（N-异丙基丙烯酰胺）嫁接的单个 DNA 分子的温度定向压缩”核酸研讨会系列。

H.Mayama: "Self-Oscillating Polymer Chain"Chem.Phys.Lett.. 330. 361-367 (2000)

H.Mayama：“自振荡聚合物链”Chem.Phys.Lett.. 330. 361-367 (2000)

Y. Yamasaki, Y. Teramoto and K. Yoshikawa: "Disappearance of the Negative Charge in Giant DNA with a Folding Transition"Biophys. J.. 80. 2823-2832 (2001)

Y. Yamasaki、Y. Teramoto 和 K. Yoshikawa：“巨型 DNA 中负电荷的消失与折叠转变”Biophys。