Nucleic Acids Research, 2002, Vol. 30, No. 10 2162-2171
© 2002 Oxford University Press
Minihelix-loop RNAs: minimal structures for aminoacylation catalysts
1Department of Biological Sciences and 2Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA
We report here an in vitro selected ribozyme, KL17, which is active in charging amino acids on its own 5'-OH group. The ribozyme consists of two catalytic domains, one of which (consisting of P5/P6/L6) recognizes amino acid substrates based on the steric environment of the side chain, whereas the other recognizes an aminoacylated oligonucleotide. The secondary structure of this ambidextrous ribozyme arranges into a pseudoknot, where L6 docks onto the 3'-terminal single-stranded region. The formation of this pseudoknot structure brings the P6 region, in which the essential catalytic core is most likely embedded, into the proximity of the 5'-OH group. Our studies show that the P6–L6 domain can be separated from the main body of KL17 and the derived P6–L6 minihelix-loop RNA can act as a trans-aminoacylation catalyst. In this report, we also compare this ribozyme with an analogous aminoacylation system previously characterized in our laboratory and illuminate the similarities and differences between these catalytic systems.
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