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4CGY

Crystal structure of the human topoisomerase III alpha-RMI1 complex

Summary for 4CGY
Entry DOI10.2210/pdb4cgy/pdb
DescriptorDNA TOPOISOMERASE 3-ALPHA, RECQ-MEDIATED GENOME INSTABILITY PROTEIN 1, MAGNESIUM ION, ... (4 entities in total)
Functional Keywordsdna replication-isomerase complex, double holliday junction dissolution, decatenation, minimal dissolvasome, dna replication/isomerase
Biological sourceHOMO SAPIENS (HUMAN)
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Total number of polymer chains2
Total formula weight111253.40
Authors
Bocquet, N.,Bunker, R.D.,Thoma, N.H. (deposition date: 2013-11-27, release date: 2014-02-12, Last modification date: 2023-12-20)
Primary citationBocquet, N.,Bizard, A.H.,Abdulrahman, W.,Larsen, N.B.,Faty, M.,Cavadini, S.,Bunker, R.D.,Kowalczykowski, S.C.,Cejka, P.,Hickson, I.D.,Thoma, N.H.
Structural and Mechanistic Insight Into Holliday-Junction Dissolution by Topoisomerase Iiialpha and Rmi1
Nat.Struct.Mol.Biol., 21:261-, 2014
Cited by
PubMed 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.
PubMed: 24509834
DOI: 10.1038/NSMB.2775
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.85 Å)
Structure validation

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