Architecture and DNA recognition elements of the Fanconi anemia FANCM-FAAP24 complex

Structure. 2013 Sep 3;21(9):1648-58. doi: 10.1016/j.str.2013.07.006. Epub 2013 Aug 8.

Abstract

Fanconi anemia (FA) is a disorder associated with a failure in DNA repair. FANCM (defective in FA complementation group M) and its partner FAAP24 target other FA proteins to sites of DNA damage. FANCM-FAAP24 is related to XPF/MUS81 endonucleases but lacks endonucleolytic activity. We report a structure of an FANCM C-terminal fragment (FANCMCTD) bound to FAAP24 and DNA. This S-shaped structure reveals the FANCM (HhH)2 domain is buried, whereas the FAAP24 (HhH)2 domain engages DNA. We identify a second DNA contact and a metal center within the FANCM pseudo-nuclease domain and demonstrate that mutations in either region impair double-stranded DNA binding in vitro and FANCM-FAAP24 function in vivo. We show the FANCM translocase domain lies in proximity to FANCMCTD by electron microscopy and that binding fork DNA structures stimulate its ATPase activity. This suggests a tracking model for FANCM-FAAP24 until an encounter with a stalled replication fork triggers ATPase-mediated fork remodeling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / chemistry
  • Catalytic Domain
  • Cell Survival / drug effects
  • Coordination Complexes / chemistry
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • DNA Damage
  • DNA Helicases / chemistry*
  • DNA Helicases / metabolism
  • DNA Repair
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Fanconi Anemia Complementation Group Proteins
  • Gene Knockdown Techniques
  • HEK293 Cells
  • Humans
  • Hydrolysis
  • Mitomycin / pharmacology
  • Models, Molecular
  • Mutagens / pharmacology
  • Nucleic Acid Conformation
  • Oligonucleotides / chemistry
  • Protein Binding
  • Protein Structure, Secondary
  • RNA, Small Interfering / genetics

Substances

  • Coordination Complexes
  • DNA-Binding Proteins
  • FAAP24 protein, human
  • Fanconi Anemia Complementation Group Proteins
  • Mutagens
  • Oligonucleotides
  • RNA, Small Interfering
  • Mitomycin
  • Adenosine Triphosphate
  • FANCM protein, human
  • DNA Helicases

Associated data

  • PDB/4BXO