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Ribozyme Catalysis of Metabolism in the RNA World

Ribozyme-Catalyzed Transcription of an Active Ribozyme

Abstract

A critical event in the origin of life is thought to have been the emergence of an RNA molecule capable of replicating a primordial RNA “genome.” Here we describe the evolution and engineering of an RNA polymerase ribozyme capable of synthesizing RNAs of up to 95 nucleotides in length. To overcome its sequence dependence, we recombined traits evolved separately in different ribozyme lineages. This yielded a more general polymerase ribozyme that was able to synthesize a wider spectrum of RNA sequences, as we demonstrate by the accurate synthesis of an enzymatically active RNA, a hammerhead endonuclease ribozyme. This recapitulates a central aspect of an RNA-based genetic system: the RNA-catalyzed synthesis of an active ribozyme from an RNA template.

via sciencemag.org

 

 

Ribozyme-catalyzed transcription of an active ribozyme.

Summary

A critical event in the origin of life is thought to have been the emergence of an RNA molecule capable of replicating a primordial RNA “genome.” Here we describe the evolution and engineering of an RNA polymerase ribozyme capable of synthesizing RNAs of up to 95 nucleotides in length. To overcome its sequence dependence, we recombined traits evolved separately in different ribozyme lineages. This yielded a more general polymerase ribozyme that was able to synthesize a wider spectrum of RNA sequences, as we demonstrate by the accurate synthesis of an enzymatically active RNA, a hammerhead endonuclease ribozyme. This recapitulates a central aspect of an RNA-based genetic system: the RNA-catalyzed synthesis of an active ribozyme from an RNA template.

Affiliation

Medical Research Council (MRC) Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.

Journal Details

Name: Science (New York, N.Y.)
ISSN: 1095-9203
Pages: 209-12

Links

 PubMed Articles

 

Exploring the New RNA World

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The large subunit of the ribosome. Starburst, active site for protein synthesis. The active site consists of RNA (white strands), not protein (orange), supporting the conclusion that the ribosome is a ribozyme.
Figure by Nenad Ban and Thomas Steitz
Copyright © Howard Hughes Medical Institute

 

Ribonuclease P: A Small Step in the RNA World

The RNA dreamtime

The RNA dreamtime

Modern cells feature proteins that might have supported a prebiotic polypeptide world but nothing indicates that RNA world ever was

  1. Charles G. Kurland

 Abstract

Modern cells present no signs of a putative prebiotic RNA world. However, RNA coding is not a sine qua non for the accumulation of catalytic polypeptides. Thus, cellular proteins spontaneously fold into active structures that are resistant to proteolysis. The law of mass action suggests that binding domains are stabilized by specific interactions with their substrates. Random polypeptide synthesis in a prebiotic world has the potential to initially produce only a very small fraction of polypeptides that can fold spontaneously into catalytic domains. However, that fraction can be enriched by proteolytic activities that destroy the unfolded polypeptides and regenerate amino acids that can be recycled into polypeptides. In this open system scenario the stable domains that accumulate and the chemical environment in which they are accumulated are linked through self coding of polypeptide structure. Such open polypeptide systems may have been the precursors to the cellular ribonucleoprotein (RNP) world that evolved subsequently.

Article first published online: 30 AUG 2010

DOI: 10.1002/bies.201000058

BioEssays

BioEssays

Volume 32Issue 10pages 866–871October 2010

 

Touching RNA

RNA can bind and sense the shapes of other molecules by feeling them with its backbone—and not just its bases. What gives RNA molecules this remarkable versatility?

By Anna Marie Pyle

34-4

What pulls catalytic RNA together
Group II introns have a conserved secondary structure consisting of six domains (magenta) that are flanked by the upstream and downstream exons (orange). In the first step of splicing (1), a bulged adenosine in domain 6 (DVI) attacks the phosphate at the 5′-splice site, becoming covalently attached to it and releasing the 5′-exon. In the second step of splicing (2), the 5′ terminus attacks the phosphate at the 3′-splice site, thereby joining the two exons (splicing them together) and releasing the lariat-shaped group II intron. The group II intron’s crystal structure is shown above, with the catalytically important domain V (DV) marked in magenta.

Read more:Touching RNA – The Scientist – Magazine of the Life Scienceshttp://www.the-scientist.com/article/display/57647/#ixzz0zxxL5WFU

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