Trivaline Molecular Complexes with Trinucleotides Form in Solution the Extended, about 1000 Å in Length Structures

Abstract

The fluorescence, flow linear dichroism and electron microscopy (EM) have shown the trivaline ability to interact in solution with certain molecules of trinucleotides. This interaction results in formation of extended structures up to several. thousand angstroms in length. Such structures were observed for trivaline complexes with homopurine, homopyrimidine or random sequences of deoxyribo- and ribonucleotides, independently of the presence or absence of the terminal 5′-phosphate residue. A model of such a structural organization is proposed. An elementary structural unit consists of a trivaline β-dimer and adsorbed trinucleotide. So, “dimeric” complex is formed. Two such “dimeric” complexes combine with each other by means of peptide-peptide contacts (as with β-sandwich). So, “tetrameric” complex is formed It has a dyad axis. Two such structural units combine with each other by means of Hoogsteen's hydrogen bonds. So, “octamreic” complex is formed. It has three mutually perpendicular dyad axes. The “octameric” complexes appear to be able to combine with each other by means of stacking interactions, and to form the regular organized aggregates consisting of many dozens of elementary units. So, “stacking” structure is formed. The “octameric” complex is the symmetry translational unit of such a stucture. The spatial position of the bases in all these structures is additionally fixed by the nucleo-peptide interactions. These aggregates have the appearance of extended structures on electron micrographs.