ジャーナル: Structure / 年: 2025 タイトル: Assembly of the Xrn2/Rat1-Rai1-Rtt103 termination complexes in mesophilic and thermophilic organisms. 著者: Alzbeta Dikunova / Nikola Noskova / Jan H Overbeck / Martin Polak / David Stelzig / David Zapletal / Karel Kubicek / Jiri Novacek / Remco Sprangers / Richard Stefl / 要旨: The 5'-3' exoribonuclease Xrn2, known as Rat1 in yeasts, terminates mRNA transcription by RNA polymerase II (RNAPII). In the torpedo model of termination, the activity of Xrn2/Rat1 is enhanced by ...The 5'-3' exoribonuclease Xrn2, known as Rat1 in yeasts, terminates mRNA transcription by RNA polymerase II (RNAPII). In the torpedo model of termination, the activity of Xrn2/Rat1 is enhanced by Rai1, which is recruited to the termination site by Rtt103, an adaptor protein binding to the RNAPII C-terminal domain (CTD). The overall architecture of the Xrn2/Rat1-Rai1-Rtt103 complex remains unknown. We combined structural biology methods to characterize the torpedo complex from Saccharomyces cerevisiae and Chaetomium thermophilum. Comparison of the structures from these organisms revealed a conserved protein core fold of the subunits, but significant variability in their interaction interfaces. We found that in the mesophile, Rtt103 utilizes an unstructured region to augment a Rai1 β-sheet, while in the thermophile Rtt103 binds to a C-terminal helix of Rai1 via its CTD-interacting domain with an α-helical fold. These different torpedo complex assemblies reflect adaptations to the environment and impact complex recruitment to RNAPII.
chain_id: A, source_name: Other, initial_model_type: in silico model
ScRai1-Rat1 PDB ID:8Q6V, ModelAngelo
chain_id: B, source_name: Other, initial_model_type: in silico model
ScRai1-Rat1 PDB ID:8Q6V, ModelAngelo
chain_id: D, residue_range: 252-273, source_name: Other, initial_model_type: in silico model
Rtt103, AlphaFold
詳細
As initial model was used previously estimated ScRai1-Rat1 dimer. The position of investigated peptide was predicted by AlphaFold and manually built into the corresponding cryo-EM using Coot. For final geometry estimation was used ISOLDE.
精密化
空間: REAL / プロトコル: FLEXIBLE FIT
得られたモデル
PDB-9fms: Cryo-EM structure of S. cerevisiae Rai1-Rat1-Rtt103(252-273) complex.