Cancer Prevention and Research Institute of Texas (CPRIT)
RR190046
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM142722
米国
引用
ジャーナル: Nucleic Acids Res / 年: 2022 タイトル: Structural and dynamic basis of DNA capture and translocation by mitochondrial Twinkle helicase. 著者: Zhuo Li / Parminder Kaur / Chen-Yu Lo / Neil Chopra / Jamie Smith / Hong Wang / Yang Gao / 要旨: Twinkle is a mitochondrial replicative helicase which can self-load onto and unwind mitochondrial DNA. Nearly 60 mutations on Twinkle have been linked to human mitochondrial diseases. Using cryo- ...Twinkle is a mitochondrial replicative helicase which can self-load onto and unwind mitochondrial DNA. Nearly 60 mutations on Twinkle have been linked to human mitochondrial diseases. Using cryo-electron microscopy (cryo-EM) and high-speed atomic force microscopy (HS-AFM), we obtained the atomic-resolution structure of a vertebrate Twinkle homolog with DNA and captured in real-time how Twinkle is self-loaded onto DNA. Our data highlight the important role of the non-catalytic N-terminal domain of Twinkle. The N-terminal domain directly contacts the C-terminal helicase domain, and the contact interface is a hotspot for disease-related mutations. Mutations at the interface destabilize Twinkle hexamer and reduce helicase activity. With HS-AFM, we observed that a highly dynamic Twinkle domain, which is likely to be the N-terminal domain, can protrude ∼5 nm to transiently capture nearby DNA and initialize Twinkle loading onto DNA. Moreover, structural analysis and subunit doping experiments suggest that Twinkle hydrolyzes ATP stochastically, which is distinct from related helicases from bacteriophages.