title: Poly(8-bromoadenylic acid): synthesis and characterization of an all-syn polynucleotide.
abstract: Poly(8-bromoadenylic acid) (poly(8-BrA)) has been synthesized by polymerization of 8-BrADP with polynucleotide phosphorylase in the presence of oligonucleotide primers. In the absence of oligonucleotides, significant (i.e. more than 1%) polymerization does not occur. Oligo(I) primer was removed selectively from the polymer with ribonuclease T1 to yield the homopolymer, poly(8-BrA). End group analysis, based on quantitative infrared measurement of the (Ip)3I-primed polymer, indicates an average degree of polymerization of about 70 residues. The primed polymers and the homopolymer appear to have similar helical structures, probably double-stranded with mutual hydrogen bonding interaction of BrA residues. Preliminary NMR observations of poly(8-BrA) with a tetrainosinic acid primer at the 5' ends of the polymer chain ((Ip)3I-(8-BrA)n) are consistent with the existence of a rigid helical structure below the melting range of the primed polymer. Above the melting range (81 degrees) the H1' coupling constants of (Ip)3I-(8-BrA)n and of polyadenylic acid (poly(A)) suggest a significantly higher population of C3' endo conformation of ribose residues in the primed polymer than in poly(A) at 81 degrees.
mesh_terms: D000249:Adenosine Monophosphate / Q000031:analogs & derivatives*; D001665:Binding Sites; D001966:Bromine; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008837:Micrococcus / Q000201:enzymology; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009841:Oligonucleotides; D011119:Polynucleotides / Q000096:biosynthesis*; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism; D012910:Snake Venoms; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013997:Time Factors
chemical_list: D009841:Oligonucleotides; D011119:Polynucleotides; D012910:Snake Venoms; D000249:Adenosine Monophosphate; D011117:Polyribonucleotide Nucleotidyltransferase; D001966:Bromine