Interaction specificity of benzimidazol group compounds with AT-containing polynucleotides.

The interaction between polynucleotides: poly(dA)-poly(dT), poly(dA-dT), poly(am2dA-dT), and the AT-specific compounds of benzimidazol group has been studied. It is been shown that these compounds bind to poly(dA)-poly(dT) and poly(dA-dT) at low and high salt concentration in solution. Poly(am2dA-dT) interacts with AT-specific compounds only at low salt, where this polynucleotide is in a B-form, but not at high salt, when the polynucleotide converts to another conformation.

Patterson methods in fibre diffraction analysis.

The potential of the Patterson methods for X-ray diffraction studies of textures is examined in DNA fibres. Patterson analysis, which is rarely used in these situations, is shown to yield important information on the preliminary interpretation of diffraction patterns and to increase the reliability of the three-dimensional structural pattern obtained for polymeric molecules. We also show how the screw symmetry of helical molecules can be used to calculate their electron density by means of the three-dimensional Patterson function.

Bh-DNA: variations of the poly[d(A)].poly[d(T)] structure within the framework of the fibre diffraction studies.

A refinement of the recent results for poly[d(A)].poly[d(T)] (Alexeev et al., J.

The structure of poly(dA).poly(dT) as revealed by an X-ray fibre diffraction.

X-ray diffraction in fibres revealed that the calcium salt of poly(dA).poly(dT) is a 10-fold double helix with a pitch of 3.23 nm.

EXAFS studies of the calcium salts of natural DNA and polydA:polydT.

Preliminary EXAFS experiments were carried out on film of the Ca salts of the synthetic polynucleotide polydA:polydT at 95%, 81%, and 76% relative humidity (r.h.) and for the Ca salt of chicken erythrocyte DNA at 81% r.

Poly(dA).poly(dT) is a B-type double helix with a distinctively narrow minor groove.

The structure of poly(dA).poly(dT) currently arouses great interest, mainly because dAn.dTn stretches are associated with considerable DNA bending.

Structure of the B DNA cationic shell as revealed by an X-ray diffraction study of CsDNA. Sequence-specific cationic stabilization of B form DNA.

Synchrotron radiation diffraction data for phage T2 CsDNA fibres have been used to determine the co-ordinates of the caesium ions in crystalline B form DNA. The R value is 0.16 for an optimized structure.

Study of DNA films by the CD, X-ray and polarization microscopy techniques.

DNA films with psi +/- CD spectra have been investigated. X-ray analysis has shown the sign of the psi spectra to be independent of the secondary structure of DNA. The appearance of the psi spectra is attended by the formation of a characteristic polygonal texture of the cholesteric type in the DNA film.