title: The limits of template-directed synthesis with nucleoside-5'-phosphoro(2-methyl)imidazolides.
abstract: In earlier work we have shown that C-rich templates containing isolated A, T or G residues and short oligo(G) sequences can be copied effectively using nucleoside-5'-phosphoro(2-methyl)imidazolides as substrates. We now show that isolated A or T residues within an oligo(G) sequence are a complete block to copying and that an isolated C residue is copied inefficiently. Replication is possible only if there are two complementary oligonucleotides each of which acts as a template to facilitate the synthesis of the other. We emphasize the severity of the problems that need to be overcome to make possible non-enzymatic replication in homogeneous aqueous solution. We conclude that an efficient catalyst was involved in the origin of polynucleotide replication.
authors.affiliation: Salk Institute for Biological Studies, San Diego, CA 92186-5800.
authors.forename: A R
authors.initials: AR
authors.lastname: Hill
authors.forename: L E
authors.initials: LE
authors.lastname: Orgel
authors.forename: T
authors.initials: T
authors.lastname: Wu
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000096:biosynthesis / Q000737:chemistry; D004261:DNA Replication; D008954:Models, Biological; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000737:chemistry*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry
chemical_list: D009711:Nucleotides; D009838:Oligodeoxyribonucleotides; D004247:DNA