Publication Date:
2014-06-12
Description:
Spontaneous changes in the reading frame of translation are rare (frequency of 10(-3) to 10(-4) per codon), but can be induced by specific features in the messenger RNA (mRNA). In the presence of mRNA secondary structures, a heptanucleotide 'slippery sequence' usually defined by the motif X XXY YYZ, and (in some prokaryotic cases) mRNA sequences that base pair with the 3' end of the 16S ribosomal rRNA (internal Shine-Dalgarno sequences), there is an increased probability that a specific programmed change of frame occurs, wherein the ribosome shifts one nucleotide backwards into an overlapping reading frame (-1 frame) and continues by translating a new sequence of amino acids. Despite extensive biochemical and genetic studies, there is no clear mechanistic description for frameshifting. Here we apply single-molecule fluorescence to track the compositional and conformational dynamics of individual ribosomes at each codon during translation of a frameshift-inducing mRNA from the dnaX gene in Escherichia coli. Ribosomes that frameshift into the -1 frame are characterized by a tenfold longer pause in elongation compared to non-frameshifted ribosomes, which translate through unperturbed. During the pause, interactions of the ribosome with the mRNA stimulatory elements uncouple EF-G catalysed translocation from normal ribosomal subunit reverse-rotation, leaving the ribosome in a non-canonical intersubunit rotated state with an exposed codon in the aminoacyl-tRNA site (A site). tRNA(Lys) sampling and accommodation to the empty A site and EF-G action either leads to the slippage of the tRNAs into the -1 frame or maintains the ribosome into the 0 frame. Our results provide a general mechanistic and conformational framework for -1 frameshifting, highlighting multiple kinetic branchpoints during elongation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4472451/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4472451/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Jin -- Petrov, Alexey -- Johansson, Magnus -- Tsai, Albert -- O'Leary, Sean E -- Puglisi, Joseph D -- GM099687/GM/NIGMS NIH HHS/ -- GM51266/GM/NIGMS NIH HHS/ -- R01 GM051266/GM/NIGMS NIH HHS/ -- R01 GM099687/GM/NIGMS NIH HHS/ -- England -- Nature. 2014 Aug 21;512(7514):328-32. doi: 10.1038/nature13428. Epub 2014 Jun 11.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Department of Applied Physics, Stanford University, Stanford, California 94305-4090, USA [2] Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA. ; Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24919156" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/genetics
;
Codon/genetics
;
DNA Polymerase III/genetics
;
Escherichia coli
;
*Frameshifting, Ribosomal
;
Kinetics
;
*Peptide Chain Elongation, Translational
;
Peptide Elongation Factor G/metabolism
;
RNA, Messenger/genetics
;
RNA, Transfer, Amino Acyl/metabolism
;
Reading Frames/genetics
;
Ribosome Subunits/chemistry/metabolism
;
Ribosomes/chemistry/*metabolism
;
Rotation
;
Time Factors
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
