THE RIBOSOME-IN-PIECES - BINDING OF ELONGATION-FACTOR EF-G TO OLIGORIBONUCLEOTIDES THAT MIMIC THE SARCIN RICIN AND THIOSTREPTON DOMAINS OF 23S RIBOSOMAL-RNA/
A. Munishkin et Ig. Wool, THE RIBOSOME-IN-PIECES - BINDING OF ELONGATION-FACTOR EF-G TO OLIGORIBONUCLEOTIDES THAT MIMIC THE SARCIN RICIN AND THIOSTREPTON DOMAINS OF 23S RIBOSOMAL-RNA/, Proceedings of the National Academy of Sciences of the United Statesof America, 94(23), 1997, pp. 12280-12284
An oligoribonucleotide (a 27-mer) that mimics the sarcin/ricin (S/R) d
omain of Escherichia coli 23S rRNA binds elongation factor EF-G; the K
-d is 6.9 mu M, whereas for binding to ribosomes it is 0.7 mu M. Bindi
ng saturates when EF-G and the S/R RNA are equimolar; at saturation 70
% of the input RNA is in complexes with EF-G. Binding of EF-G to S/R R
NA does not require GTP but is inhibited by GDP; the inhibition by GDP
is overcome by GTP, The effects of mutations of the S/R domain nucleo
tides G2655, A2660, and G2661 suggest that EF-G recognizes the conform
ation of the RNA rather than the identity of the nucleotides. EF-G als
o binds to an oligoribonucleotide (an 84-mer) that has the thiostrepto
n region of 23S rRNA; however, EF-G binds independently to S/R and thi
ostrepton oligoribonucleotides.