Alpha-sarcin cleavage of ribosomal RNA is inhibited by the binding of elongation factor G or thiostrepton to the ribosome.
The translocation reaction catalyzed by elongation factor G (EF-G) is inhibited either by alpha-sarcin cleavage of 23S rRNA or by the binding of thiostrepton to the E. coli ribosome. Here we show that the transitory binding of EF-G and GDP to the ribosome inhibited the rate of alpha-sarcin cleavage and that stabilization of this binding with fusidic acid completely prevented alpha-sarcin cleavage. A similar pattern of inhibition was seen upon the binding of elongation factor 2 to the S. cerevisiae ribosome. The irreversible binding of the antibiotic thiostrepton to the E. coli ribosome, on the other hand, decreased the rate of cleavage by alpha-sarcin approximately 2-fold. These results suggest that the alpha-sarcin site is located within the ribosomal domain for EF-G binding and that the conformation of this site is affected by the binding of thiostrepton.
Miller
S P
SP
Department of Biochemistry, University of Minnesota, Minneapolis 55455.
Bodley
J W
JW
D001230:Aspergillus / Q000378:metabolism*; D001665:Binding Sites; D004591:Electrophoresis, Polyacrylamide Gel; D004722:Endoribonucleases; D004926:Escherichia coli / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors / Q000378:metabolism*; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D013883:Thiostrepton / Q000378:metabolism*
D005656:Fungal Proteins; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors; D012338:RNA, Ribosomal, 23S; C014801:alpha-sarcin; D004722:Endoribonucleases; D013883:Thiostrepton