Table 1 |
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Ribozyme activities relevant for the emergence of the translation machinery from the RNA world |
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| Reaction |
Characteristics of the ribozyme |
References |
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| Aminoacyl adenylate synthesis |
Low efficiency formation of leucyl and phenylalanyl adenylates observed with a 114-nucleotide
ribozyme. |
[132] |
| Self-aminoacylation |
Self-aminoacylation of a 43-nulceotide ribozyme with phenylalanine using phe-AMP as
the substrate. A 77-nucleotide RNA catalyzed the same reaction with a specificity
and aminoacylatin rate greater that those of PheRS. |
[51, 146] |
| RNA 3'-aminoacylation In-trans |
The smallest ribozyme capable of non-specific tRNA aminoacylation consists of 29 nucleotides.
A 45-nucleotide ribozyme has been obtained with a broad spectrum of activity toward
diverse tRNAs and amino acids. Larger ribozymes with highly specific and efficient
aminoacylation activity reported. |
[51, 147, 148] |
| In vitro selected peptidyltransferase ribozymes |
Several ribozymes selected to form dipeptides from an amino acid esterified to AMP
or a oligonucleotide and a free amino acid. Structural similarity observed between
peptidyltransferase sibozymes and the relevant portion of 23S rRNA. Formation of Phe-Phe-tRNA
reported for the 29-nucleotide aminoacylating ribozyme. |
[128, 129, 149, 150] |
| Ribosomal peptidyltransferase |
In the ribosomal large subunits, the peptidyltransferase center maps to an are containing
only RNA, leading to the conclusion that the reaction is catalyzed by a ribozyme;
however, identification of the active residues remains elusive. |
[151–154] |
| Ribonucleotide polymerization |
Ribozymes capable of extending a pre-annealed RNA primer by 10–14 nucleotides selected
from a pool of RNA ligase ribozymes |
[53, 54] |
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Wolf and Koonin Biology Direct 2007 2:14 doi:10.1186/1745-6150-2-14 |
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