Chiral selection in poly(C)-directed synthesis of oligo(G)

  title={Chiral selection in poly(C)-directed synthesis of oligo(G)},
  author={G. F. Joyce and G. M. Visser and C. V. Boeckel and J. Boom and L. Orgel and J. Westrenen},
Theories of the origin of optical asymmetry in living systems place fundamental importance on the amplification of optical asymmetry by an autocatalytic process1–3. The replication of a polynucleotide is one obvious choice for such an autocatalytic growth mechanism. If an optically homogeneous polynucleotide could replicate by directing the polymerization of monomers of the same handedness, while excluding monomers of the opposite handedness, its chiral descendants would come to dominate what… Expand
RNA-Catalyzed Cross-Chiral Polymerization of RNA.
In vitro evolution is employed to select cross-chiral polymerases that use either mono- or trinucleotide substrates that are activated as the 5´ triphosphate, which enables the trin DNA polymerase to react 102-103-fold faster than its ancestor and to accept substrates with all possible sequence combinations. Expand
Remote Enantioselection Transmitted by an Achiral Peptide Nucleic Acid Backbone.
It seems possible that some PNA sequences could act as catalysts, analogous to ribozymes, even though PNA lacks clear metal binding sites, and the incorporation of as few as two chiral nucleotides could then impose chiral specificity on the system. Expand
A Cross-chiral RNA Polymerase Ribozyme
A cross-chiral RNA polymerase is developed using in vitro evolution starting from a population of random-sequence RNAs, where the enzyme’s activity is sufficient to generate full-length copies of its enantiomer through the templated joining of 11 component oligonucleotides. Expand
The chiral code: From DNA primary structures to quaternary assemblies
Nucleic acids are characterized by a predominant right-handed helical configuration that derives from the chirality of the sugar moiety. Hitherto, only “local” effects of this helical asymmetry,Expand
Chiral Monomers Ensure Orientational Specificity of Monomer Binding During Polymer Self-Replication
Here it is argued that when polymerization is constrained to proceed in only one direction along the template, as in DNA, evolution favors chiral monomers and homochiral polymers and the requirement of orientational specificity leads to monomer chirality, by using a known relationship between rotational and reflection symmetry elements, within the constraint that the resultant polymers are helical. Expand
A route to enantiopure RNA precursors from nearly racemic starting materials.
The emergence of molecules of single chirality from complex, multi-component mixtures supports the robustness of this synthesis process under potential prebiotic conditions and provides a plausible explanation for the single-handedness of biological molecules before the emergence of self-replicating informational polymers. Expand
A chiroselective peptide replicator
It is reported that a 32-residue peptide replicator, designed according to earlier principles, is capable of efficiently amplifying homochiral products from a racemic mixture of peptide fragments through a chiroselective autocatalytic cycle, supporting the idea that self-replicating polypeptides could have played a key role in the origin of homochirality on Earth. Expand
PNAs — A prebiotic template? enantiomeric cross-inhibition on the nonchiral template and the rearrangement of peptide nucleic acids in aqueous solution
Prebiotic syntheses of potentially chiral monomers always yield racemic mixtures. Living systems, however, utilize L-aminoacids and D-nucleotides in their biopolymers. The generation of opticalExpand
Pyranosyl-RNA: chiroselective self-assembly of base sequences by ligative oligomerization of tetranucleotide-2',3'-cyclophosphates (with a commentary concerning the origin of biomolecular homochirality).
It is extrapolate that sets of tetramers with different but mutually fitting base sequences can be expected to co-oligomerize stochastically and generate sequence libraries consisting of predominantly homochiral (D)- and (L)-oligomers, starting from the racemic mixture of tetamers containing all possible diastereomers. Expand
Attempted nonenzymatic template-directed oligomerizations on a polyadenylic acid template: Implications for the nature of the first genetic material
The results of the experiments suggest that pyrimidines were not part of the original replicating system on the primitive Earth, and it is suggested that phosphate was absent as well. Expand


Oligomerization of (guanosine 5'-phosphor)-2-methylimidazolide on poly(C). An RNA polymerase model.
Guanosine 5′-phosphor)-2-methylimidazolide (2-MeImpG) undergoes an efficient, buffer-independent, template-directed oligomerization in the presence of poly(C) at pH values above 7.6. Expand
Temperature-dependence of the template-directed synthesis of oligoguanylates.
The oligomerization of (guanosine 5'-phosphor)-2-methylimidazolide on a poly(C) template proceeds efficiently at temp. as high as 37 degrees, although the helical complex formed by the template andExpand
Catalysis of accurate poly(C)-directed synthesis of 3'-5'-linked oligoguanylates by Zn2+.
If poly(C) is incubated with ImpG and an equimolar quantity of the 5′-phosphorimidazolides of adenosine, uridine or cytidine, in the presence of Zn 2+, ImpG is incorporated at least 200 times more efficiently than “incorrect” nucleotides. Expand
Efficient catalysis of polycytidylic acid-directed oligoguanylate formation by Pb2+.
Abstract Pb 2+ is a very effective catalyst for the template-directed self-condensation of guanosine 5′-phosphorimidazolide on a polycytidylate template. In the presence of 0.01 m -Pb 2+ at 0 °C, upExpand
  • G. Wald
  • Chemistry, Medicine
  • Annals of the New York Academy of Sciences
  • 1957
I think that organisms acquired optical activity, not as a gift from the inorganic world, but through processes of selection out of originally racemic mixtures, and the nature of such processes is outlined. Expand