Ribosome-bound eukaryotic elongation factor 2 protects 5 S rRNA from modification.
The interaction between eukaryotic elongation factor eEF-2 and reconstituted 80 S ribosomes was investigated by analyzing the accessibility of 5 S ribosomal RNA for chemical and enzymatic modification. Ribosomes reconstituted from derived subunits were modified, and the positions of the modified sites were identified by primer extension using a 5 S rRNA-specific probe. All reactive sites were located between nucleotides 38 and 99, and most of them were found in putative single-stranded regions of the 5 S rRNA. Conversion of the ribosomes to the post-translocation type of particles by treatment with the translational inhibitor ricin resulted in the exposure of 3 additional bases for chemical modification, suggesting that the 5 S rRNA was more exposed in this type of ribosome. After binding of eEF-2 in complex with the non-hydrolyzable GTP analogue guanosine 5'-(beta, gamma-methylene)-triphosphate, most of the exposed bases in the 5 S rRNA were protected against both chemical and enzymatic modification.
Holmberg
L
L
Department of Zoological Cell Biology, Stockholm University, Arrhenius Laboratories, Sweden.
Melander
Y
Y
Nygård
O
O
D000818:Animals; D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D005095:Exoribonucleases; D051379:Mice; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D012341:RNA, Ribosomal, 5S / Q000378:metabolism*
D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D012341:RNA, Ribosomal, 5S; D005095:Exoribonucleases; C023871:nuclease H