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Published on: March 25, 2020
In vitro selection of RNA aptamer against Escherichia coli release factor 1
Shinsuke Sando1, Atsushi Ogawa, Teruyuki Nishi
1Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan. ssando@sbchem.kyoto-u.ac.jp
Abstract:
A pool of 84-nt RNAs containing a randomized sequence of 50 nt was selected against gel-immobilized Escherichia coli release factor 1 (RF-1) responsible for translation termination at amber (UAG) stop codon. The strongest aptamer (class II-1) obtained from 43 clones bound to RF-1, but not to UAA/UGA-targeting RF-2, with Kd = 30+/-6 nM (SPR). A couple of unpaired hairpin domains in the aptamer were suggested as the sites of attachment of RF-1. By binding to and hence inhibiting the action of RF-1 specifically or bio-orthogonally, aptamer class II-1 enhanced the amber suppression efficiency in the presence of an anticodon-adjusted (CUA) suppressor tRNA without practically damaging the protein translation machinery of the cell-free extract of E. coli, as confirmed by the translation of amber-mutated (gfp(amber141) or gfp(amber178)) and wild-type (gfp(wild)) genes of GFP.
