New insight into the recognition of branched DNA structure by junction-resolving enzymes.
Junction-resolving enzymes are nucleases that exhibit structural selectivity for the four-way (Holliday) junction in DNA. In general, these enzymes both recognize and distort the structure of the junction. New insight into the molecular recognition processes has been provided by two recent co-crystal structures of resolving enzymes bound to four-way DNA junctions in highly contrasting ways. T4 endonuclease VII binds the junction in an open conformation to an approximately flat binding surface whereas T7 endonuclease I envelops the junction, which retains a much more three-dimensional structure. Both proteins make contacts with the DNA backbone over an extensive area in order to generate structural specificity. The comparison highlights the versatility of Holliday junction resolution, and extracts some general principles of recognition.
Déclais
Anne-Cécile
AC
Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dundee DD1 5EH, UK.
Lilley
David Mj
DM
D000818:Animals; D001665:Binding Sites; D004262:DNA Restriction Enzymes / Q000737:chemistry / Q000378:metabolism; D045566:DNA, Cruciform / Q000737:chemistry* / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000737:chemistry / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000378:metabolism; D045565:Holliday Junction Resolvases / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011487:Protein Conformation
D045566:DNA, Cruciform; D004706:Endodeoxyribonucleases; D004262:DNA Restriction Enzymes; D045565:Holliday Junction Resolvases; D003850:Deoxyribonuclease I; C035571:endodeoxyribonuclease VII