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Structure and Function of Biopolymers
Structure of the calcium salt of poly(dA) : poly(dT) as revealed by the X-ray diffraction analysis in fibres
1Alexeev D. G., 1Lipanov A. A., 1Skuratovsky I. Ya.
  1. Institute of Molecular Genetics, Academy of Sciences of the USSR
    Moscow, USSR


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 conformation being close to C2'-endo (δ = 138В°), 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.


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