A HIERARCHY OF TRIVALINE NUCLEIC-ACID COMPLEXES AND COMPACT STRUCTURES .3. COMPLEXES OF TRIVALINE WITH TRINUCLEOTIDES IN SOLUTION FORM RODLIKE STRUCTURES SIMILAR-TO-1000 ANGSTROM LONG

It was found that complexes of trivaline with some trinucleotides are capable of forming extended (up to several thousand Angstrom) fiberlik e structures in solution. Among such trinucleotides are both deoxyribo - and ribo-related random sequences either with or without the 5'-term inal phosphate group as well as homopurinic and homopyrimidinic trinuc leotides. We proposed a model for such structures which is based on a tetrameric complex composed of a trivaline tetramer and two trinucleot ides. Two such complexes associate to form an octamer [1-4]. It has th ree mutually perpendicular dyad axes. The spatial position of the nucl eic bases in this structure is additionally fixed by nucleopeptide int eractions. These interactions favor both formation of hydrogen bonds b etween trinucleotides of different tetrameric complexes and base stack ing between the bases of each trinucleotide. The octameric complexes c an form regular aggregates involving dozens of elementary units arrang ed in a stack. Electron microscopy revealed that these aggregates appe ar as extended fiberlike structures.