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Evolution of Ribozymes in an RNA World
Muller
Chemistry & Biology Vol 16, Issue 8, 28 Aug. 2009, pp 797-798
Overview: Ribozymes (catalytic RNAs) were the center of a presumed RNA world in the early origin of life. In this issue, Lau and Unrau show evidence that an RNA world could have used a similar evolutionary pathway as most proteins do.
Muller
Chemistry & Biology Vol 16, Issue 8, 28 Aug. 2009, pp 797-798
Overview: Ribozymes (catalytic RNAs) were the center of a presumed RNA world in the early origin of life. In this issue, Lau and Unrau show evidence that an RNA world could have used a similar evolutionary pathway as most proteins do.
A Promiscuous Ribozyme Promotes Nucleotide Synthesis in Addition to Ribose Chemistry
Lau, Unrau
Chemistry & Biology Vol 16, Issue 8, 28 Aug 2009, pp 815-825
Summary: Here we report the in vitro selection of an unusual ribozyme that efficiently performs nucleotide synthesis even though it was selected to perform a distinctly different sugar chemistry. This ribozyme, called pR1, when derivatized with ribose 5-phosphate (PR) at its 3′ terminus and incubated with 6-thioguanine, produces two interconverting thiol-containing products corresponding to a Schiff base and its Amadori rearranged product. Consistent with this hypothesis, removing the 2-hydroxyl from the PR substrate results in only a single product. Surprisingly, as this was not selected for, switching the tethered PR substrate to 5-phosphoribosyl 1-pyrophosphate results in the synthesis of 6-thioguanosine 5′-monophosphate. The discovery that a ribozyme can promote such distinct reactions spontaneously demonstrates that an RNA-mediated metabolism early in evolution could have evolved important new functionalities via ribozyme promiscuity
Lau, Unrau
Chemistry & Biology Vol 16, Issue 8, 28 Aug 2009, pp 815-825
Summary: Here we report the in vitro selection of an unusual ribozyme that efficiently performs nucleotide synthesis even though it was selected to perform a distinctly different sugar chemistry. This ribozyme, called pR1, when derivatized with ribose 5-phosphate (PR) at its 3′ terminus and incubated with 6-thioguanine, produces two interconverting thiol-containing products corresponding to a Schiff base and its Amadori rearranged product. Consistent with this hypothesis, removing the 2-hydroxyl from the PR substrate results in only a single product. Surprisingly, as this was not selected for, switching the tethered PR substrate to 5-phosphoribosyl 1-pyrophosphate results in the synthesis of 6-thioguanosine 5′-monophosphate. The discovery that a ribozyme can promote such distinct reactions spontaneously demonstrates that an RNA-mediated metabolism early in evolution could have evolved important new functionalities via ribozyme promiscuity
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