自然结构和分子生物学2013-09-05 2:58 AM

Dynamics of translation by single ribosomes through mRNA secondary structures : Nature Structural & Molecular Biology : Nature Publishing Group

During protein synthesis, the ribosome translates nucleotide triplets in single-stranded mRNA into polypeptide sequences. Strong downstream mRNA secondary structures, which must be unfolded for translation, can slow or even halt protein synthesis. Here we used single-molecule fluorescence resonance energy transfer to determine reaction rates for specific steps within the elongation cycle as the Escherichia coli ribosome encounters stem-loop or pseudoknot mRNA secondary structures. Downstream stem-loops containing 100% GC base pairs decrease the rates of both tRNA translocation within the ribosome and deacylated tRNA dissociation from the ribosomal exit site (E site). Downstream stem-loops or pseudoknots containing both GC and AU pairs also decrease the rate of tRNA dissociation, but they have little effect on tRNA translocation rate. Thus, somewhat unexpectedly, unfolding of mRNA secondary structures is more closely coupled to E-site tRNA dissociation than to tRNA translocation.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

自然结构和分子生物学

0 Following 0 Fans 0 Projects 31 Articles

SIMILAR ARTICLES

The 26S proteasome is the major eukaryotic ATP-dependent protease, responsible for regulating the proteome through degradation of ubiquitin-tagged subs

Read More

Homeostatic mechanisms regulate the abundance of several components in small-RNA pathways. We used Drosophila and mammalian systems to demonstrate a co

Read More

Argonaute proteins interact with small RNAs that guide them to complementary target RNAs, thus leading to inhibition of gene expression. Some but not a

Read More

A paramount task in RNA interference research is to decipher the complex biology of cellular effectors, exemplified in humans by four pleiotropic Argon

Read More

The anaphase-promoting complex/cyclosome (APC/C) is a ~1.5-MDa multiprotein E3 ligase enzyme that regulates cell division by promoting timely ubiquitin

Read More

The repair of DNA double-strand breaks (DSBs) is critical for the maintenance of genome integrity. The first step in DSB repair by homologous recombina

Read More

Many Saccharomyces cerevisiae genes encode antisense transcripts, some of which are unstable and degraded by the exosome component Rrp6. Loss of Rrp6 r

Read More

The anoxygenic phototrophic bacterium Rhodobacter sphaeroides uses different energy sources, depending on environmental conditions including aerobic re

Read More

Glucocorticoid receptor (GR) binds to genomic response elements and regulates gene transcription with cell and gene specificity. Within a response elem

Read More

Transcription termination is essential to generate functional RNAs and to prevent disruptive polymerase collisions resulting from concurrent transcript

Read More