DSSR-derived G-quadruplex features in PDB entry 2kka
- Human telomere DNA two-tetrad quadruplex structure in k+ solution
- Zhang, Z., Dai, J., Veliath, E., Jones, R.A., Yang, D.: (2010) "Structure of a two-G-tetrad intramolecular G-quadruplex formed by a variant human telomeric sequence in K+ solution: insights into the interconversion of human telomeric G-quadruplex structures." Nucleic Acids Res., 38, 1009-1021.
- Human telomeric DNA G-quadruplex has been considered as an attractive target for cancer therapeutic intervention. The telomeric sequence shows intrinsic structure polymorphism. Here we report a novel intramolecular G-quadruplex structure formed by a variant human telomeric sequence in K(+) solution. This sequence forms a basket-type intramolecular G-quadruplex with only two G-tetrads but multiple-layer capping structures formed by loop residues. While it is shown that this structure can only be detected in the specifically truncated telomeric sequences without any 5'-flanking residues, our results suggest that this two-G-tetrad conformation is likely to be an intermediate form of the interconversion of different telomeric G-quadruplex conformations.
- G4 notes
- 2 G-tetrads, 1 G4 helix, 1 G4 stem · 2(-LwD+Ln), basket(2+2), UDDU
1 glyco-bond=s--s groove=w-n- planarity=0.061 type=planar nts=4 GGGG A.DG2,A.DG9,A.DG21,A.DG15 2 glyco-bond=-ss- groove=w-n- planarity=0.084 type=planar nts=4 GGGG A.DG3,A.DG8,A.DG20,A.DG16
In DSSR, a G4-helix is defined by stacking interactions of G-tetrads, regardless of backbone connectivity, and may contain more than one G4-stem.
Helix#1, 2 G-tetrad layers, INTRA-molecular, with 1 stem
In DSSR, a G4-stem is defined as a G4-helix with backbone connectivity. Bulges are also allowed along each of the four strands.