9FFF image
Entry Detail
PDB ID:
9FFF
EMDB ID:
Title:
dsDNA-FANCD2-FANCI complex
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2024-05-23
Release Date:
2024-07-31
Method Details:
Experimental Method:
Resolution:
3.68 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Fanconi anemia protein FANCD2
Chain IDs:A
Chain Length:1475
Number of Molecules:1
Biological Source:Gallus gallus
Polymer Type:polypeptide(L)
Description:Fanconi anemia complementation group I
Chain IDs:B
Chain Length:1338
Number of Molecules:1
Biological Source:Gallus gallus
Polymer Type:polydeoxyribonucleotide
Description:DNA (32-MER)
Chain IDs:C (auth: S)
Chain Length:32
Number of Molecules:1
Biological Source:synthetic construct
Polymer Type:polydeoxyribonucleotide
Description:DNA (33-MER)
Chain IDs:D (auth: T)
Chain Length:33
Number of Molecules:1
Biological Source:synthetic construct
Ligand Molecules
Primary Citation
FANCD2-FANCI surveys DNA and recognizes double- to single-stranded junctions.
Nature 632 1165 1173 (2024)
PMID: 39085614 DOI: 10.1038/s41586-024-07770-w

Abstact

DNA crosslinks block DNA replication and are repaired by the Fanconi anaemia pathway. The FANCD2-FANCI (D2-I) protein complex is central to this process as it initiates repair by coordinating DNA incisions around the lesion1. However, D2-I is also known to have a more general role in DNA repair and in protecting stalled replication forks from unscheduled degradation2-4. At present, it is unclear how DNA crosslinks are recognized and how D2-I functions in replication fork protection. Here, using single-molecule imaging, we show that D2-I is a sliding clamp that binds to and diffuses on double-stranded DNA. Notably, sliding D2-I stalls on encountering single-stranded-double-stranded (ss-ds) DNA junctions, structures that are generated when replication forks stall at DNA lesions5. Using cryogenic electron microscopy, we determined structures of D2-I on DNA that show that stalled D2-I makes specific interactions with the ss-dsDNA junction that are distinct from those made by sliding D2-I. Thus, D2-I surveys dsDNA and, when it reaches an ssDNA gap, it specifically clamps onto ss-dsDNA junctions. Because ss-dsDNA junctions are found at stalled replication forks, D2-I can identify sites of DNA damage. Therefore, our data provide a unified molecular mechanism that reconciles the roles of D2-I in the recognition and protection of stalled replication forks in several DNA repair pathways.

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Disease

Primary Citation of related structures