Biopolymers and cell. 1986. Volume 2. № 4. 189 - 195
D. G. Alexeev, A. A. Lipanov, I. Ya. Skuratovsky
STRUCTURE OF THE CALCIUM SALT OF POLY(dA) : POLY(dT) AS REVEALED BY THE X-RAY DIFFRACTION ANALYSIS IN FIBRES
Summary
Fibre X-ray diffraction study of the calcium salt of poly(dA) :poly(dT) has resulted in a model of this polynucleotide which is a ten-fold double helix with the pitch of 3.23 nm. Antiparallel sugar phosphate chains are fully equivalent in the model, deoxyribose con¬formation being close to C2'-endo (8 = 138°), and it may be regarded as member of B-family structures. A revised structure of Na-poly(dA) : poly(dT) is suggested, which is also of the B-type and with the highly similar opposite chains.