Mitochondrial DNA Replication group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709.
Molecular Microscopy Consortium, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709.
Proc Natl Acad Sci U S A. 2022 Aug 9;119(32):e2207459119. doi: 10.1073/pnas.2207459119. Epub 2022 Aug 1.
Twinkle is the mammalian helicase vital for replication and integrity of mitochondrial DNA. Over 90 Twinkle helicase disease variants have been linked to progressive external ophthalmoplegia and ataxia neuropathies among other mitochondrial diseases. Despite the biological and clinical importance, Twinkle represents the only remaining component of the human minimal mitochondrial replisome that has yet to be structurally characterized. Here, we present 3-dimensional structures of human Twinkle W315L. Employing cryo-electron microscopy (cryo-EM), we characterize the oligomeric assemblies of human full-length Twinkle W315L, define its multimeric interface, and map clinical variants associated with Twinkle in inherited mitochondrial disease. Cryo-EM, crosslinking-mass spectrometry, and molecular dynamics simulations provide insight into the dynamic movement and molecular consequences of the W315L clinical variant. Collectively, this ensemble of structures outlines a framework for studying Twinkle function in mitochondrial DNA replication and associated disease states.
Twinkle 是一种在哺乳动物中线粒体 DNA 复制和完整性方面至关重要的解旋酶。超过 90 种 Twinkle 解旋酶疾病变体与进行性眼外肌麻痹和共济失调神经病等线粒体疾病有关。尽管具有重要的生物学和临床意义，但 Twinkle 是人类最小线粒体复制体中唯一尚未进行结构表征的剩余组成部分。在这里，我们展示了人源 Twinkle W315L 的三维结构。通过使用冷冻电镜（cryo-EM），我们对人全长 Twinkle W315L 的寡聚体组装进行了表征，确定了其多聚体界面，并绘制了与遗传性线粒体疾病中 Twinkle 相关的临床变体图谱。冷冻电镜、交联质谱和分子动力学模拟为了解 W315L 临床变体的动态运动和分子后果提供了线索。总的来说，这些结构组合为研究 Twinkle 在线粒体 DNA 复制和相关疾病状态中的功能提供了一个框架。
