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Title | Mechanisms of loading and release of the 9-1-1 checkpoint clamp. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 29, Issue 4, Page 369-375, Year 2022 |
Publish date | Mar 21, 2022 |
Authors | Juan C Castaneda / Marina Schrecker / Dirk Remus / Richard K Hite / |
PubMed Abstract | Single-stranded or double-stranded DNA junctions with recessed 5' ends serve as loading sites for the checkpoint clamp, 9-1-1, which mediates activation of the apical checkpoint kinase, ATR. However, ...Single-stranded or double-stranded DNA junctions with recessed 5' ends serve as loading sites for the checkpoint clamp, 9-1-1, which mediates activation of the apical checkpoint kinase, ATR. However, the basis for 9-1-1's recruitment to 5' junctions is unclear. Here, we present structures of the yeast checkpoint clamp loader, Rad24-replication factor C (RFC), in complex with 9-1-1 and a 5' junction and in a post-ATP-hydrolysis state. Unexpectedly, 9-1-1 adopts both closed and planar open states in the presence of Rad24-RFC and DNA. Moreover, Rad24-RFC associates with the DNA junction in the opposite orientation of processivity clamp loaders with Rad24 exclusively coordinating the double-stranded region. ATP hydrolysis stimulates conformational changes in Rad24-RFC, leading to disengagement of DNA-loaded 9-1-1. Together, these structures explain 9-1-1's recruitment to 5' junctions and reveal new principles of sliding clamp loading. |
External links | Nat Struct Mol Biol / PubMed:35314831 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.2 - 3.9 Å |
Structure data | EMDB-25422, PDB-7st9: EMDB-25423, PDB-7stb: EMDB-25424: Mec3 focus refinement of Rad24-RFC:9-1-1:DNA in the open state EMDB-25425: Rad24-Rfc4 focus refinement of Rad24-RFC-ADP EMDB-25426, PDB-7ste: |
Chemicals | ChemComp-AGS: ChemComp-MG: ChemComp-GLU: ChemComp-THR: ChemComp-ADP: ChemComp-HOH: ChemComp-ATP: |
Source |
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Keywords | REPLICATION/DNA / DNA damage / DNA replication / DNA sliding clamp / REPLICATION / REPLICATION-DNA complex |