Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.
Institute of Applied Physics of Seoul National University, Seoul, South Korea.
Commun Biol. 2024 Jul 19;7(1):881. doi: 10.1038/s42003-024-06557-z.
DNA-loop extrusion is considered to be a universal principle of structural maintenance of chromosome (SMC) proteins with regard to chromosome organization. Despite recent advancements in structural dynamics studies that involve the use of cryogenic-electron microscopy (Cryo-EM), atomic force microscopy (AFM), etc., the precise molecular mechanism underlying DNA-loop extrusion by SMC proteins remains the subject of ongoing discussions. In this context, we propose a scrunching model that incorporates the anisotropic motion of SMC folding with a baton-pass mechanism, offering a potential explanation of how a "DNA baton" is transferred from the hinge domain to a DNA pocket via an anisotropic hinge motion. This proposed model provides insights into how SMC proteins unidirectionally extrude DNA loops in the direction of loop elongation while also maintaining the stability of a DNA loop throughout the dynamic process of DNA-loop extrusion.
DNA 环伸出被认为是结构维持染色体（SMC）蛋白的普遍原则，就染色体组织而言。尽管最近在涉及使用低温电子显微镜（Cryo-EM）、原子力显微镜（AFM）等的结构动力学研究方面取得了进展，但 SMC 蛋白通过 DNA 环伸出的精确分子机制仍然是正在讨论的主题。在这种情况下，我们提出了一个卷曲模型，该模型将 SMC 折叠的各向异性运动与接力棒机制结合在一起，为如何通过各向异性铰链运动将“DNA 接力棒”从铰链域传递到 DNA 口袋提供了一个潜在的解释。该模型提供了深入了解 SMC 蛋白如何在 DNA 环伸出的动态过程中沿着环伸长的方向单向地伸出 DNA 环，同时保持 DNA 环的稳定性。
