Synthesis and characterization of informational molecules of early earth

Abstract

All processes in extant biology are facilitated by information encoded in polymers Therefore the origin of informational molecules had to be a crucial process in the origin of life on Earth An important molecule in this context is RNA and the RNA World has been hypothesized as a pivotal step in the transition from chemistry to biology However the RNA molecule is comprised of intra molecular bonds which are prone to hydrolysis under the harsh conditions that are thought to have been prevalent on the early Earth 1 Furthermore the formation of nucleotides with extant bases and their subsequent polymerization both have been problematic Certain environmental niches such as volcanic geo thermal pools may allow the formation of RNA like polymers Dehydration rehydration DH RH conditions which mimic diurnal or seasonal cycles result in formation of kinetic traps which may facilitate uphill polymerization reactions 2 However the low pH and high temperature conditions that are required for such polymerization also result in the cleavage of the N glycosidic bond thereby producing oligomers with abasic sites 3 In the initial part of the present study we set out to characterize the effect of prolonged DH RH cycling on the stability of resultant molecules and also looked at how it might affect the product distribution Our observations indicate lower fitness for modern nucleobases under prebiotically relevant conditions These results are also supported by older experiments wherein formation of nucleosides with extant bases itself was shown to be difficult Alternate bases on the other hand have resulted in formation of nucleosides with higher yields suggesting a viable and prebiotically relevant solution to the longstanding 8220 nucleoside problem 8221 4 We also recently demonstrated the synthesis of a plausible pre RNA World nucleotide using ribose 5 monophosphate rMP and barbituric acid BA as the base analog under dry heating conditions 5 This result was simultaneously also demonstrated by the Hud group thus strengtheni newline newline