Four-stranded DNA helices: conformational analysis of regular poly(dT).poly(dA).poly(dA).poly(dT) helices with various types of base binding.
The paper presents results obtained in conformational analysis of homopolymeric four-stranded poly(dT).poly(dA).poly(dA).poly(dT) DNA helices in which the pairs of strands with identical bases are parallel and have a two-fold symmetry axis. All possible models of base binding to yield a symmetric complex have been considered. The dihedral angles of sugar-phosphate backbones and helix parameters, which are consistent with the minima of conformational energy for four-stranded DNAs, have been determined using the results of optimization of conformational energy calculated at atom-atom approximation. Potential energy is shown to depend on the structure of base complexes and on the mutual orientation of unlike strands. Possible biological functions of four-stranded helices are discussed.
Chernyi
A A
AA
V.A. Engelhardt Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
Lysov YuP
Il'ychova
I A
IA
Zibrov
A S
AS
Shchyolkina
A K
AK
Borisova
O F
OF
Mamaeva
O K
OK
Florentiev
V L
VL
D001482:Base Composition; D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011089:Polydeoxyribonucleotides / Q000737:chemistry
D011089:Polydeoxyribonucleotides; D004247:DNA