Open AccessDistance Measurement by Energy Transfer: The 3′ End of 16‐S RNA and Proteins S4 and S17 of the Ribosome of Escherichia coli
Author(s) -
EPE Bernd,
WOOLLEY Paul,
STEINHÄUSER Klaus G.,
LITTLECHILD Jennifer
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb07042.x
Subject(s) - ribosome , ribonucleoprotein , protein subunit , escherichia coli , ribosomal rna , transfer rna , rna , chemistry , energy transfer , biophysics , biochemistry , biology , microbiology and biotechnology , chemical physics , gene
Escherichia coli ribosomal proteins S4 and S17 were specifically labelled at their thiol groups with the acetylaminoethyl‐dansyl and/or bimane fluorophores. Each formed a complex with 16‐S RNA and, when the other 30‐S ribosomal proteins were added, a complete 30‐S subunit with at least partial activity. If the 3′ end of the RNA was also labelled (with fluorescein) then the distance between the two fluorophores could be measured by Förster‐type energy transfer. The result for S4 was 6.0 nm (60 Å) in the ribonucleoprotein complex and 5.6 nm (56 Å) in the 30‐S subunit, and for S17 6.3 nm (63 Å) in the complex and 6.2 nm (62 Å) in the subunit. There is no evidence for a major change in the relative disposition of the 3′ and 5′ ends of the 16‐S RNA during formation of the 30‐S subunit. Sources of error are discussed, including the question of multiple labelling. In order to measure more accurately the extent of energy transfer a procedure based upon enzymic digestion was developed and is detailed in this paper.