National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM107239
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
GM127428
National Institutes of Health/National Cancer Institute (NIH/NCI)
CA008748
引用
ジャーナル: Nat Struct Mol Biol / 年: 2022 タイトル: Mechanisms of loading and release of the 9-1-1 checkpoint clamp. 著者: Juan C Castaneda / Marina Schrecker / Dirk Remus / Richard K Hite / 要旨: 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.