8E2L

Structure of Lates calcarifer Twinkle helicase with ATP and DNA

Summary for 8E2L

• Entry DOI: 10.2210/pdb8e2l/pdb
• EMDB information: 27842 27843 27844 27845
• Descriptor: Twinkle mtDNA helicase, DNA (5'-D(P*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*T)-3'), ADENOSINE-5'-TRIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: helicase mitochondrion, replication-dna complex, replication/dna
• Biological source: Lates calcarifer (barramundi perch); More
• Total number of polymer chains: 7
• Total formula weight: 374964.33

Authors

Gao, Y.,Li, Z. (deposition date: 2022-08-15, release date: 2022-11-02, Last modification date: 2024-06-12)

Primary citation

Li, Z.,Kaur, P.,Lo, C.Y.,Chopra, N.,Smith, J.,Wang, H.,Gao, Y.
Structural and dynamic basis of DNA capture and translocation by mitochondrial Twinkle helicase.
Nucleic Acids Res., 50:11965-11978, 2022

PubMed Abstract: 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.

PubMed: 36400570
DOI: 10.1093/nar/gkac1089

Experimental method

ELECTRON MICROSCOPY (3.51 Å)