TY - JOUR
T1 - Interactions of the TnaC nascent peptide with rRNA in the exit tunnel enable the ribosome to respond to free tryptophan
AU - Martínez, Allyson K.
AU - Gordon, Emily
AU - Sengupta, Arnab
AU - Shirole, Nitin
AU - Klepacki, Dorota
AU - Martinez-Garriga, Blanca
AU - Brown, Lewis M.
AU - Benedik, Michael
AU - Yanofsky, Charles
AU - Mankin, Alexander S.
AU - Vazquez-Laslop, Nora
AU - Sachs, Matthew S.
AU - Cruz-Vera, Luis R.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - A transcriptional attenuation mechanism regulates expression of the bacterial tnaCAB operon. This mechanism requires ribosomal arrest induced by the regulatory nascent TnaC peptide in response to free L-tryptophan (L-Trp). In this study we demonstrate, using genetic and biochemical analyses, that in Escherichia coli, TnaC residue I19 and 23S rRNA nucleotide A2058 are essential for the ribosome's ability to sense free L-Trp. We show that the mutational change A2058U in 23S rRNA reduces the concentration dependence of L-Trpmediated tna operon induction, whereas the TnaC I19L change suppresses this phenotype, restoring the sensitivity of the translating A2058U mutant ribosome to free L-Trp. These findings suggest that interactions between TnaC residue I19 and 23S rRNA nucleotide A2058 contribute to the creation of a regulatory L-Trp binding site within the translating ribosome.
AB - A transcriptional attenuation mechanism regulates expression of the bacterial tnaCAB operon. This mechanism requires ribosomal arrest induced by the regulatory nascent TnaC peptide in response to free L-tryptophan (L-Trp). In this study we demonstrate, using genetic and biochemical analyses, that in Escherichia coli, TnaC residue I19 and 23S rRNA nucleotide A2058 are essential for the ribosome's ability to sense free L-Trp. We show that the mutational change A2058U in 23S rRNA reduces the concentration dependence of L-Trpmediated tna operon induction, whereas the TnaC I19L change suppresses this phenotype, restoring the sensitivity of the translating A2058U mutant ribosome to free L-Trp. These findings suggest that interactions between TnaC residue I19 and 23S rRNA nucleotide A2058 contribute to the creation of a regulatory L-Trp binding site within the translating ribosome.
UR - http://www.scopus.com/inward/record.url?scp=84893244181&partnerID=8YFLogxK
U2 - 10.1093/nar/gkt923
DO - 10.1093/nar/gkt923
M3 - Article
C2 - 24137004
AN - SCOPUS:84893244181
SN - 0305-1048
VL - 42
SP - 1245
EP - 1256
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 2
ER -