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A dynamic competition between release factor 2 and the tRNA Sec decoding UGA at the recoding site of Escherichia coli formate dehydrogenase H
Author(s) -
Mansell John B.,
Guévremont Diane,
Poole Elizabeth S.,
Tate Warren P.
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.24.7284
Subject(s) - biology , library science , computer science
Factors affecting competition between termination and elongation in vivo during translation of the fdhF selenocysteine recoding site (UGA) were studied with wild‐type and modified fdhF sequences. Altering sequences surrounding the recoding site UGA without affecting RNA secondary structure indicated that the kinetics of stop signal decoding have a significant influence on selenocysteine incorporation efficiency. The UGA in the wild‐type fdhF sequence remains ‘visible’ to the factor and forms a site‐directed cross‐link when mRNA stem–loop secondary structure is absent, but not when it is present. The timing of the secondary structure unfolding during translation may be a critical feature of competition between release factor 2 and tRNA Sec for decoding UGA. Increasing the cellular concentration of either of these decoding molecules for termination or selenocysteine incorporation showed that they were able to compete for UGA by a kinetic competition that is dynamic and dependent on the Escherichia coli growth rate. The tRNA Sec ‐mediated decoding can compete more effectively for the UGA recoding site at lower growth rates, consistent with anaerobic induction of fdhF expression.