title: [Structure of d(GT)n repeating sequences with parallel and antiparallel chains].
abstract: The ability of oligonucleotides 3'-d(GT)5pO(CH2)5Opd(GT)5-5' (anti[d(GT)]) and 3'-d(GT)5pO(CH2)6Opd(GT)5-3' (par[d(GT)]) to form hairpins and higher associates is studied. Optical methods of thermal denaturation and circular dichroism as well as the fluorescence of ethidium bromide and acridine orange bound to oligonucleotides were used. At room temperatures the formation of hairpin structure with parallel and antiparallel strands is possible. Thermodynamic parameters of par[d(GT)] and anti[d(GT)] are similar and equal to delta H = -15 kcal/mol, delta S = -50 cal/mol. deg. In the temperature range 3-10 degrees C par[d(GT)] and anti[d(GT)] form four-stranded structures with parallel chains, in which layers of four G-residues alternate with unpaired T-residues being bulged out easily. On comparison of occurrence of alternating (GT)n, (GC)n and (G)n sequences in genome it can be stated that (GT)n biological functions could be connected with conformational possibilities of the four-stranded parallel structures with unpaired T-residues.
authors.forename: O F
authors.initials: OF
authors.lastname: Borisova
authors.forename: A K
authors.initials: AK
authors.lastname: Shchelkina
authors.forename: O K
authors.initials: OK
authors.lastname: Mamaeva
authors.forename: Iu P
authors.initials: IuP
authors.lastname: Lysov
authors.forename: A A
authors.initials: AA
authors.lastname: Chernyĭ
authors.forename: A A
authors.initials: AA
authors.lastname: Gorin
authors.forename: E N
authors.initials: EN
authors.lastname: Timofeev
authors.forename: V L
authors.initials: VL
authors.lastname: Florent'ev
mesh_terms: D002942:Circular Dichroism; D004996:Ethidium / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D012091:Repetitive Sequences, Nucleic Acid; D013050:Spectrometry, Fluorescence
chemical_list: D011089:Polydeoxyribonucleotides; C017650:polydeoxy(guanine-thymine) nucleotide; D004996:Ethidium
vernacular_title: Struktura povtoriaiushchikhsia posledovatel'nosteĭ d(GT)n s parallel'nymi i antiparallel'nymi tsepiami.