3G65: Crystal Structure Of The Human Rad9-rad1-hus1 Dna Damage Checkpoint Complex

Rad9, Rad1, and Hus1 form a heterotrimeric complex (9-1-1) that is loaded onto DNA at sites of DNA damage. DNA-loaded 9-1-1 activates signaling through the Chk1 arm of the DNA damage checkpoint response via recruitment and stimulation of ATR. Additionally, 9-1-1 may play a direct role in facilitating DNA damage repair via interaction with a number of DNA repair enzymes. We have now determined the crystal structure of the human 9-1-1 complex, revealing a toroidal structure with a similar architecture to the homotrimeric PCNA DNA-binding clamp. The structure explains the formation of a unique heterotrimeric arrangement and reveals significant differences among the three subunits in the sites implicated in binding to the clamp loader and to ligand proteins. Biochemical analysis reveals a single repair enzyme-binding site on 9-1-1 that can be blocked competitively by the PCNA-binding cell-cycle regulator p21(cip1/waf1).
PDB ID: 3G65Download
MMDB ID: 72906
PDB Deposition Date: 2009/2/6
Updated in MMDB: 2013/09
Experimental Method:
x-ray diffraction
Resolution: 2.9  Å
Source Organism:
Similar Structures:
Biological Unit for 3G65: trimeric; determined by author and by software (PISA)
Molecular Components in 3G65
Label Count Molecule
Proteins (3 molecules)
Cell Cycle Checkpoint Control Protein Rad9a(Gene symbol: RAD9A)
Molecule annotation
Cell Cycle Checkpoint Protein Rad1(Gene symbol: RAD1)
Molecule annotation
Checkpoint Protein Hus1(Gene symbol: HUS1)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB