[Interaction of tripeptides containing arginine and tyrosine (or phenylalanine) residues with synthetic polynucleotides and DNA of various origins].

Model peptides--L-Arg-Gly-L-Arg, L-Arg-L-Tyr-L-Arg and L-Arg-L-Phe-L-Arg bind to different DNAs and synthetic polynucleotides and are found in the major groove of the double helix. Polynucleotide complexes containing L-Arg-Gly-L-Arg were studied in order to consider the influence of the arginine residues on the polynucleotide melting temperature. It was shown, that L-Arg-L-Tyr-L-Arg and L-Arg-L-Phe--L-Arg lowers the melting temperature in all polynucleotides studied.

B-Z transition in poly(dG-dC).poly(dG-dC) in the presence of formaldehyde amino derivatives.

It was shown by circular dichroism that the B-Z transition of poly(dG-dC).poly(dG-dC) in high NaCl concentrations occurred more rapidly in the presence of formaldehyde and Tris. The product of formaldehyde and glycine interaction induces changes in the poly(dG-dC).

[Interaction of the peptide antibiotic bacitracin with DNA and synthetic polynucleotides].

The aim of the present paper was to study the specific character of interaction of peptide antibiotic bacitracin with DNA and to estimate the interaction constant. The influence of bacitracin on bacteriophage DNA restriction by HindIII and SmaI endonucleases was studied. The possibility of arranging the polynucleotide template by small ligands was shown.

[Possible mechanism of specific protein-nucleic acid interaction].

It has been supposed that stereochemical fitness of amino acids into the cavities associated with their codons is used for specific recognition of nucleic acids by the proteins. In accordance with this hypothesis, amino acid side chains can insert into the cavity resulting from inverting the middle base of a nucleotide triplet in DNA. Certain experimental data seem to support the hypothesis.