Download MendeleySen1 architecture: RNA-DNA hybrid resolution, autoregulation, and insights into SETX inactivation in AOA2.
Appel, C.D., Bermek, O., Dandey, V.P., Wood, M., Viverette, E., Williams, J.G., Bouvette, J., Riccio, A.A., Krahn, J.M., Borgnia, M.J., Williams, R.S.(2023) Mol Cell 83: 3692
- PubMed: 37832548
- DOI: https://doi.org/10.1016/j.molcel.2023.09.024
- Primary Citation of Related Structures:
8FTH, 8FTK, 8FTM - PubMed Abstract:
The senataxin (SETX, Sen1 in yeasts) RNA-DNA hybrid resolving helicase regulates multiple nuclear transactions, including DNA replication, transcription, and DNA repair, but the molecular basis for Sen1 activities is ill defined. Here, Sen1 cryoelectron microscopy (cryo-EM) reconstructions reveal an elongated inchworm-like architecture. Sen1 is composed of an amino terminal helical repeat Sen1 N-terminal (Sen1N) regulatory domain that is flexibly linked to its C-terminal SF1B helicase motor core (Sen1 Hel ) via an intrinsically disordered tether. In an autoinhibited state, the Sen1 Sen1N domain regulates substrate engagement by promoting occlusion of the RNA substrate-binding cleft. The X-ray structure of an activated Sen1 Hel engaging single-stranded RNA and ADP-SO 4 shows that the enzyme encircles RNA and implicates a single-nucleotide power stroke in the Sen1 RNA translocation mechanism. Together, our data unveil dynamic protein-protein and protein-RNA interfaces underpinning helicase regulation and inactivation of human SETX activity by RNA-binding-deficient mutants in ataxia with oculomotor apraxia 2 neurodegenerative disease.
Organizational Affiliation:
Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
