Nonenzymatic oligomerization on templates containing phosphodiester-linkedacyclic glycerol nucleic acid analogues

Nonenzymatic oligomerization reactions represent a model for studying the p rebiotic replication of informational macromolecules. To explore the fitnes s of acyclic oligonucleotides in these reactions, we have synthesized a ser ies of DNA hairpins appended with templates incorporating atactic glyceryl cytosine residues, Atactic glyceryl cytosine units are found to impede, but not to block, template-directed oligomerization of guanosine 5'-phosphoro- 2-methylimidazole (2-MeImpG). Evidence suggests that both D and L glyceryl nucleoside configurations at a given template position contribute to produc t formation. The stability of DNA duplexes bearing isolated glyceryl cytosi ne residues has also been investigated. Duplex thermal denaturation experim ents indicate that an atactic glyC.dG base-pair is intermediate in stabilit y between a dC.dG pair and a dT.dG mismatch.