title: [Structure of polyriboguanylic acid in solution].
abstract: The electron microscopic data and the CD spectra of poly(G) have shown that the transition of a freeze-dried preparation of poly(G) from a "metastable" to a "stable" form is the transition of the four-stranded poly(G) from the globular form to the linear one. The observed phenomenon of the formation of long four-stranded poly(G) fibers (4--5 nm in diameter and 200-2000 nm in length) is suggested to be a result of a joint of the initial poly(G) molecules (50--80 nm in length) due to noncovalent binding ("sticking") of their free one-, double- or three-stranded ends. This phenomenon has permitted us not only to compare the thickness of low molecular weight poly (G) preparations under different conditions but to observe directly the existence of a large number of double-stranded (2--3 nm in diameter) regions ("defects") in four -stranded poly(G) fibers. The data obtained have shown that under certain conditions (high temperature, low pH, etc.) the four-stranded poly(G) fibers break down with the formation of two-stranded poly(G) fibers whose hydrogen bond systems depend on the conditions of their formation.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002942:Circular Dichroism; D005612:Freeze Drying; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D009690:Nucleic Acid Conformation; D011068:Poly G; D011131:Polyribonucleotides; D012996:Solutions; D013696:Temperature; D014867:Water
chemical_list: D011131:Polyribonucleotides; D012996:Solutions; D014867:Water; D011068:Poly G
vernacular_title: Struktura poliriboguanilovoĭ kisloty v rastvore.