J. Biol. Chem., Vol. 265, Issue 14, 7894-7899, 05, 1990
Identification of a rRNA/chloramphenicol interaction site within the peptidyltransferase center of the 50 S subunit of the Escherichia coli ribosome
RT Marconi, JS Lodmell and WE Hill
Division of Biological Sciences, University of Montana, Missoula 59812.
We have used oligodeoxyribonucleotide probes to investigate possible
interactions between chloramphenicol and portions of the rRNA contained
within the peptidyltransferase center of the Escherichia coli ribosome.
Oligodeoxyribonucleotide probes complementary to bases 2448-2454, 2468-
2482, and 2497-2505 of 23 S rRNA were hybridized to 50 S subunits in situ.
Probe binding was qualitatively assessed by sucrose gradient
centrifugation. Each probe was shown to bind specifically with its intended
binding site through digestion of the rRNA within the RNA/DNA
hetero-duplexes with RNase H and analysis of the digestion fragments using
gel electrophoresis. Competitive binding experiments were conducted between
each probe and the antibiotics chloramphenicol and erythromycin. The
binding of a probe complementary to bases 2497-2505 was attenuated by 70%
upon the binding of chloramphenicol. A probe complementary to bases
2468-2482 showed an increase in binding of 14% while binding of a probe
complementary to bases 2448-2454 was not affected by chloramphenicol
binding. Erythromycin did not affect the binding of any of these probes to
50 S subunits. These results suggest that bases within the 2497-2505 region
of 23 S rRNA in E. coli may be involved in a chloramphenicol/rRNA
interaction.