Origin of informational polymers: Differential stability of phosphoester bonds in ribomonomers and ribooligomers

We have measured the stabilities of the bonds that are critical for determining the half-life of ribonucleotides and the β-glycosidic and 3′- and 5′-phosphoester bonds. Stabilities were measured under a wide range of temperatures and water/formamide ratios. The stability of phosphodiester bonds in oligoribonucleotides was determined in the same environments. The comparison of bond stabilities in the monomer versus the polymer forms of the ribo compounds revealed that physico-chemical conditions exist in which polymerization is thermodynamically favored. These conditions were compared with those determining a similar behavior for 2′- deoxyribonucleosides, deoxyribonucleotides, and deoxyribooligonucleotides and were shown to profoundly differ. The implications of these facts on the origin of informational polymers are discussed. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc.