Abstract
DNA double-crossover molecules containing two Holliday junctions have been prepared and treated with endonuclease VII, the resolvase from bacteriophage T4. One molecule contains antiparallel double-helical domains, and the other molecule contains parallel domains. The parallel double-crossover model system has been made tractable by closing the free ends of the molecule, to convert it to a catenane. The products resulting from the two substrates differ substantially. The molecule containing antiparallel helical domains is cleaved three nucleotides 3′ to the crossover points, in a fashion similar to single Holliday junction analogs. The molecule containing parallel helical domains is cleaved, but the major points of scission are five nucleotides 5′ to a branch point on the crossover strands and six nucleotides 3′ to the same branch point on the non-crossover strands. The major sites of scission reflect features of molecular symmetry in each case, suggesting that the resolvase recognizes structural features. The cleavage results suggest that the antiparallel structure is the natural substrate, if the Holliday junction is unconstrained within the cell. It is straightforward to reconcile antiparallel Holliday junctions with the conventional parallel paradigm of recombination. Nevertheless, the cleavage of the parallel molecule shows that a parallel substrate could also be cleaved symmetrically by endonuclease VII (but with different products) if the molecule were constrained to assume that conformation within the cell.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3896-3905 |
| Number of pages | 10 |
| Journal | Biochemistry |
| Volume | 33 |
| Issue number | 13 |
| State | Published - 1994 |
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- Biochemistry
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Cleavage of double-crossover molecules by T4 endonuclease VII. / Seeman, Nadrian.
In: Biochemistry, Vol. 33, No. 13, 1994, p. 3896-3905.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cleavage of double-crossover molecules by T4 endonuclease VII
AU - Seeman, Nadrian
PY - 1994
Y1 - 1994
N2 - DNA double-crossover molecules containing two Holliday junctions have been prepared and treated with endonuclease VII, the resolvase from bacteriophage T4. One molecule contains antiparallel double-helical domains, and the other molecule contains parallel domains. The parallel double-crossover model system has been made tractable by closing the free ends of the molecule, to convert it to a catenane. The products resulting from the two substrates differ substantially. The molecule containing antiparallel helical domains is cleaved three nucleotides 3′ to the crossover points, in a fashion similar to single Holliday junction analogs. The molecule containing parallel helical domains is cleaved, but the major points of scission are five nucleotides 5′ to a branch point on the crossover strands and six nucleotides 3′ to the same branch point on the non-crossover strands. The major sites of scission reflect features of molecular symmetry in each case, suggesting that the resolvase recognizes structural features. The cleavage results suggest that the antiparallel structure is the natural substrate, if the Holliday junction is unconstrained within the cell. It is straightforward to reconcile antiparallel Holliday junctions with the conventional parallel paradigm of recombination. Nevertheless, the cleavage of the parallel molecule shows that a parallel substrate could also be cleaved symmetrically by endonuclease VII (but with different products) if the molecule were constrained to assume that conformation within the cell.
AB - DNA double-crossover molecules containing two Holliday junctions have been prepared and treated with endonuclease VII, the resolvase from bacteriophage T4. One molecule contains antiparallel double-helical domains, and the other molecule contains parallel domains. The parallel double-crossover model system has been made tractable by closing the free ends of the molecule, to convert it to a catenane. The products resulting from the two substrates differ substantially. The molecule containing antiparallel helical domains is cleaved three nucleotides 3′ to the crossover points, in a fashion similar to single Holliday junction analogs. The molecule containing parallel helical domains is cleaved, but the major points of scission are five nucleotides 5′ to a branch point on the crossover strands and six nucleotides 3′ to the same branch point on the non-crossover strands. The major sites of scission reflect features of molecular symmetry in each case, suggesting that the resolvase recognizes structural features. The cleavage results suggest that the antiparallel structure is the natural substrate, if the Holliday junction is unconstrained within the cell. It is straightforward to reconcile antiparallel Holliday junctions with the conventional parallel paradigm of recombination. Nevertheless, the cleavage of the parallel molecule shows that a parallel substrate could also be cleaved symmetrically by endonuclease VII (but with different products) if the molecule were constrained to assume that conformation within the cell.
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M3 - Article
VL - 33
SP - 3896
EP - 3905
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 13
ER -