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The complex between a four‐way DNA junction and T7 endonuclease I
Author(s) -
Déclais AnneCécile,
Fogg Jonathan M.,
Freeman Alasdair D. J.,
Coste Franck,
Hadden Jonathan M.,
Phillips Simon E. V.,
Lilley David M. J.
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg132
Subject(s) - nucleic acid , library science , dna , biology , biochemistry , computer science
The junction‐resolving enzyme endonuclease I is selective for the structure of the DNA four‐way (Holliday) junction. The enzyme binds to a four‐way junction in two possible orientations, with a 4:1 ratio, opening the DNA structure at the centre and changing the global structure into a 90° cross of approximately coaxial helices. The nuclease cleaves the continuous strands of the junction in each orientation. Binding leads to pronounced regions of protection of the DNA against hydroxyl radical attack. Using all this information together with the known structure of the enzyme and the structure of the Bgl I–DNA complex, we have constructed a model of the complex of endonuclease I and a DNA junction. This shows how the enzyme is selective for the structure of a four‐way junction, such that both continuous strands can be accommodated into the two active sites so that a productive resolution event is possible.