scholarly journals Prebiotic Chemistry and the Origin of the RNA World

2004 ◽  
Vol 39 (2) ◽  
pp. 99-123 ◽  
Author(s):  
Orgel Leslie E.
Author(s):  
Falk Wachowius ◽  
James Attwater ◽  
Philipp Holliger

AbstractThe emergence of functional cooperation between the three main classes of biomolecules – nucleic acids, peptides and lipids – defines life at the molecular level. However, how such mutually interdependent molecular systems emerged from prebiotic chemistry remains a mystery. A key hypothesis, formulated by Crick, Orgel and Woese over 40 year ago, posits that early life must have been simpler. Specifically, it proposed that an early primordial biology lacked proteins and DNA but instead relied on RNA as the key biopolymer responsible not just for genetic information storage and propagation, but also for catalysis, i.e. metabolism. Indeed, there is compelling evidence for such an ‘RNA world’, notably in the structure of the ribosome as a likely molecular fossil from that time. Nevertheless, one might justifiably ask whether RNA alone would be up to the task. From a purely chemical perspective, RNA is a molecule of rather uniform composition with all four bases comprising organic heterocycles of similar size and comparable polarity and pKa values. Thus, RNA molecules cover a much narrower range of steric, electronic and physicochemical properties than, e.g. the 20 amino acid side-chains of proteins. Herein we will examine the functional potential of RNA (and other nucleic acids) with respect to self-replication, catalysis and assembly into simple protocellular entities.


2016 ◽  
Vol 2 (3) ◽  
Author(s):  
James Tour

Two new papers on prebiotic chemistry are reviewed by James Tour. The first claims to find further support for the RNA World hypothesis and the second suggests that nucleotide formation and selection may have been robust processes on the prebiotic Earth. Tour expresses skepticism on both counts.


2017 ◽  
Vol 114 (43) ◽  
pp. 11327-11332 ◽  
Author(s):  
Ben K. D. Pearce ◽  
Ralph E. Pudritz ◽  
Dmitry A. Semenov ◽  
Thomas K. Henning

Before the origin of simple cellular life, the building blocks of RNA (nucleotides) had to form and polymerize in favorable environments on early Earth. At this time, meteorites and interplanetary dust particles delivered organics such as nucleobases (the characteristic molecules of nucleotides) to warm little ponds whose wet–dry cycles promoted rapid polymerization. We build a comprehensive numerical model for the evolution of nucleobases in warm little ponds leading to the emergence of the first nucleotides and RNA. We couple Earth’s early evolution with complex prebiotic chemistry in these environments. We find that RNA polymers must have emerged very quickly after the deposition of meteorites (less than a few years). Their constituent nucleobases were primarily meteoritic in origin and not from interplanetary dust particles. Ponds appeared as continents rose out of the early global ocean, but this increasing availability of “targets” for meteorites was offset by declining meteorite bombardment rates. Moreover, the rapid losses of nucleobases to pond seepage during wet periods, and to UV photodissociation during dry periods, mean that the synthesis of nucleotides and their polymerization into RNA occurred in just one to a few wet–dry cycles. Under these conditions, RNA polymers likely appeared before 4.17 billion years ago.


2019 ◽  
Author(s):  
Tom H. Wright ◽  
Constantin Giurgiu ◽  
Aleksandar Radakovic ◽  
Derek K. O’Flaherty ◽  
Lijun Zhou ◽  
...  

ABSTRACTAchieving multiple cycles of RNA replication within a model protocell would be a critical step towards demonstrating a path from prebiotic chemistry to cellular biology. Any model for early life based on an ‘RNA world’ must account for RNA strand cleavage and hydrolysis, which would degrade primitive genetic information and lead to an accumulation of truncated, phosphate-terminated strands. We show here that cleavage of the phosphodiester backbone is not an endpoint for RNA replication. Instead, 3′ -phosphate terminated RNA strands are able to participate in template-directed copying reactions with activated ribonucleotide monomers. These reactions form a pyrophosphate linkage, the stability of which we have characterized in the context of RNA copying chemistry. We found that the pyrophosphate bond is relatively stable within an RNA duplex and in the presence of chelated magnesium. Under these conditions, pyrophosphate-RNA can act as a temporary ‘patch’ to template the polymerization of canonical ribonucleotides, suggesting a plausible non-enzymatic pathway for the salvage and recovery of genetic information following strand cleavage.


2004 ◽  
Vol 8 (6) ◽  
pp. 629-633 ◽  
Author(s):  
Randall A Hughes ◽  
Michael P Robertson ◽  
Andrew D Ellington ◽  
Matthew Levy

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Noam Prywes ◽  
J Craig Blain ◽  
Francesca Del Frate ◽  
Jack W Szostak

The nonenzymatic replication of RNA is a potential transitional stage between the prebiotic chemistry of nucleotide synthesis and the canonical RNA world in which RNA enzymes (ribozymes) catalyze replication of the RNA genomes of primordial cells. However, the plausibility of nonenzymatic RNA replication is undercut by the lack of a protocell-compatible chemical system capable of copying RNA templates containing all four nucleotides. We show that short 5′-activated oligonucleotides act as catalysts that accelerate primer extension, and allow for the one-pot copying of mixed sequence RNA templates. The fidelity of the primer extension products resulting from the sequential addition of activated monomers, when catalyzed by activated oligomers, is sufficient to sustain a genome long enough to encode active ribozymes. Finally, by immobilizing the primer and template on a bead and adding individual monomers in sequence, we synthesize a significant part of an active hammerhead ribozyme, forging a link between nonenzymatic polymerization and the RNA world.


2018 ◽  
Author(s):  
S.M. MacKenzie ◽  
◽  
Elizabeth Turtle ◽  
Ralph Lorenz ◽  
Jani Radebaugh ◽  
...  
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