title: Polynucleotide duplexes based on poly(7-deazaadenylic acid).
abstract: In order to find a poly(A)-poly(U) analog which could not form a triple-stranded complex and which would have a sufficiently high thermal stability to survive under physiological conditions, the interaction of poly(7-deazaadenylic acid) (poly(c-7A)) with modified polyuridylic acids was examined. Mixing curves constructed by the method of continuous variation, isosbestic points and thermal melting profiles proved that poly(c-7A) formed only 1:1 complex with polyribothymidylic acid and poly(5-bromouridylic acid) (Tm values of 50 and 72 degrees C respectively, in 0.15 M NaCl, 0.01 M KH2 PO4, 0.001 M MgCl2, pH7). In addition poly(c-7A) formed a 1:1 complex with poly(I) (Tm equals 22 degrees C in 0.46 M salt, pH 7), and presumed duplexes were observed in the interaction of poly(c-7A) with poly(dT), poly(2'-azido-2'-deoxyuridylic acid) and poly(2'-O-methyluridylic acid) (Tm values of 35, 32 and 41 degrees C respectively, in 0.10 M NaCl, pH7).
mesh_terms: D000227:Adenine Nucleotides; D000469:Alkaline Phosphatase; D001483:Base Sequence; D006358:Hot Temperature; D007700:Kinetics; D008837:Micrococcus / Q000201:enzymology; D009691:Nucleic Acid Denaturation; D010179:Pancreas; D010727:Phosphoric Diester Hydrolases; D011119:Polynucleotides; D011117:Polyribonucleotide Nucleotidyltransferase; D012260:Ribonucleases; D012910:Snake Venoms; D013056:Spectrophotometry, Ultraviolet; D014372:Tubercidin
chemical_list: D000227:Adenine Nucleotides; D011119:Polynucleotides; D012910:Snake Venoms; D011117:Polyribonucleotide Nucleotidyltransferase; D012260:Ribonucleases; D000469:Alkaline Phosphatase; D010727:Phosphoric Diester Hydrolases; D014372:Tubercidin