Background: Provocative recent reports indicate that the large subunit
s of either prokaryotic or eukaryotic ribosomes have the capacity to p
romote refolding of denatured enzymes. Results: Salt-washed Escherichi
a coli ribosomes are shown to promote refolding of denatured rhodanese
. The ability of the ribosomes to carry out renaturation is a property
of the 50S ribosomal subunit, specifically the 23S rRNA. Refolding an
d release of enzymatically active rhodanese leaves the ribosomes in an
inactive state or conformation for subsequent rounds of refolding. In
active ribosomes can be activated by elongation factor G (EF-G) plus G
TP or by cleavage of their 23S rRNA by alpha-sarcin. Activation by eit
her mechanism is strongly inhibited by the EF-G.GDP.fusidic acid compl
ex. Conclusions: Large subunits of E. coli ribosomes, specifically 23S
rRNA, have the capacity to mediate refolding of denatured rhodanese.
Refolding activity is related to the state or conformation of ribosome
s that is promoted by EF-G. Activation by either mechanism is strongly
inhibited by the EF-G.GDP.fusidic acid complex.