Chemical Etiology of Nucleic Acid Structure: Comparing Pentopyranosyl-(2'→4') Oligonucleotides with RNA

Abstract
All four members of the family of pentopyranosyl-(2′→4′) oligonucleotide systems that contain β-ribo-, β-xylo-, α-lyxo-, or α-arabinopyranosyl units as repeating sugar building blocks are found to be much stronger Watson-Crick base-pairing systems than RNA. The α-arabinopyranosyl system is the strongest of all and in fact belongs to the strongest oligonucleotide base-pairing systems known. Whatever the chemical determinants by which nature selected RNA as a genetic system, maximization of base-pairing strengths within the domain of pentose-derived oligonucleotide systems was not the critical selection criterion.
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