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PDBsum entry 4cgy

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protein metals Protein-protein interface(s) links
DNA replication/isomerase PDB id
4cgy
Jmol
Contents
Protein chains
619 a.a.
205 a.a.
Metals
_MG
Waters ×44
PDB id:
4cgy
Name: DNA replication/isomerase
Title: Crystal structure of the human topoisomerase iii alpha-rmi1
Structure: DNA topoisomerase 3-alpha. Chain: a. Fragment: residues 2-753. Synonym: DNA topoisomerase iii alpha. Engineered: yes. Recq-mediated genome instability protein 1. Chain: b. Fragment: residues 1-219. Synonym: blm-associated protein of 75 kda, blap75, faap75.
Source: Homo sapiens. Human. Organism_taxid: 9606. Expressed in: trichoplusia ni. Expression_system_taxid: 7111. Expression_system_cell_line: high five (bti-tn-5b1-4).
Resolution:
2.85Å     R-factor:   0.198     R-free:   0.231
Authors: N.Bocquet,R.D.Bunker,N.H.Thoma
Key ref: N.Bocquet et al. (2014). Structural and mechanistic insight into Holliday-junction dissolution by topoisomerase IIIα and RMI1. Nat Struct Mol Biol, 21, 261-268. PubMed id: 24509834 DOI: 10.1038/nsmb.2775
Date:
27-Nov-13     Release date:   12-Feb-14    
PROCHECK
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 Headers
 References

Protein chain
Pfam   ArchSchema ?
Q13472  (TOP3A_HUMAN) -  DNA topoisomerase 3-alpha
Seq:
Struc:
 
Seq:
Struc:
1001 a.a.
619 a.a.
Protein chain
Pfam   ArchSchema ?
Q9H9A7  (RMI1_HUMAN) -  RecQ-mediated genome instability protein 1
Seq:
Struc:
 
Seq:
Struc:
625 a.a.
205 a.a.
Key:    PfamA domain  PfamB domain  Secondary structure

 Enzyme reactions 
   Enzyme class: Chain A: E.C.5.99.1.2  - Dna topoisomerase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: ATP-independent breakage of single-stranded DNA, followed by passage and rejoining.
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     chromosome   1 term 
  Biological process     DNA topological change   1 term 
  Biochemical function     DNA binding     3 terms  

 

 
DOI no: 10.1038/nsmb.2775 Nat Struct Mol Biol 21:261-268 (2014)
PubMed id: 24509834  
 
 
Structural and mechanistic insight into Holliday-junction dissolution by topoisomerase IIIα and RMI1.
N.Bocquet, A.H.Bizard, W.Abdulrahman, N.B.Larsen, M.Faty, S.Cavadini, R.D.Bunker, S.C.Kowalczykowski, P.Cejka, I.D.Hickson, N.H.Thomä.
 
  ABSTRACT  
 
Repair of DNA double-strand breaks via homologous recombination can produce double Holliday junctions (dHJs) that require enzymatic separation. Topoisomerase IIIα (TopIIIα) together with RMI1 disentangles the final hemicatenane intermediate obtained once dHJs have converged. How binding of RMI1 to TopIIIα influences it to behave as a hemicatenane dissolvase, rather than as an enzyme that relaxes DNA topology, is unknown. Here, we present the crystal structure of human TopIIIα complexed to the first oligonucleotide-binding domain (OB fold) of RMI1. TopIII assumes a toroidal type 1A topoisomerase fold. RMI1 attaches to the edge of the gate in TopIIIα through which DNA passes. RMI1 projects a 23-residue loop into the TopIIIα gate, thereby influencing the dynamics of its opening and closing. Our results provide a mechanistic rationale for how RMI1 stabilizes TopIIIα-gate opening to enable dissolution and illustrate how binding partners modulate topoisomerase function.