Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Textbook explanation of mRNA translation may need rethinking

27.06.2005


Our understanding of how messenger RNAs are translated into proteins is challenged by new research published today in the Open Access journal Journal of Biology. The study suggests that EF-G, the GTPase that facilitates tRNA translocation in bacteria, enters the ribosome bound to a different guanine nucleotide than previously thought – GDP, not GTP. The ribosome itself then seems to act as the guanine-nucleotide exchange factor, not some as-yet-unidentified factor as previously assumed. This finding questions the prevailing model for RNA translocation.

According to the textbook model EF-G provides the energy needed for the translocation phase of translation by bringing GTP into the ribosome where GTP is subsequently hydrolysed into GDP.

Andrei Zavialov, Vasili Hauryliuk and Måns Ehrenberg from Uppsala University in Sweden first performed an important purification step ensuring that their GTP was not contaminated by GDP (and vice versa), as had been the case with previous studies using these purified components. They next measured the affinity of EF-G for GTP and GDP. Their results strongly suggest that EF-G is bound to GDP in the cytoplasm and that it binds to the pre-translocation complex - composed of the ribosome, tRNA and mRNA strand – as a EF-G-GDP complex. The ribosome itself then seems to act as a GTP exchange factor that swaps GDP for GTP, which results in a modification in the structure of the ribosome. This triggers partial translocation of the mRNA, which is completed after GTP hydrolysis. “Our results suggest that the ribosome plays a previously unidentified dual role of both guanine-nucleotide exchange factor and GTPase-activating protein” explain the authors. EF-G then detaches from the ribosome in its GDP-bound form, ready to be used again by another ribosome.



These findings differ radically from all previous models and as such may represent a considerable step forward in our understanding of translocation, a fundamental mechanism in protein synthesis and gene expression. RNA translation is a highly conserved mechanism and these results using a bacterial system are likely to be applicable to higher organisms as well. This should spur more research in the field to confirm or disprove the findings and give us a clearer picture of RNA translation. In particular, the present clarification of the translocation process at the biochemical level may allow a deeper understanding of how relative movements of the ribosomal subunits can accomplish thousands of translocation events without frame-shifting or loss of tRNA-bound nascent protein chains during peptide elongation.

Juliette Savin | alfa
Further information:
http://www.biomedcentral.com

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New gene catalog of ocean microbiome reveals surprises

18.08.2017 | Life Sciences

Astrophysicists explain the mysterious behavior of cosmic rays

18.08.2017 | Physics and Astronomy

AI implications: Engineer's model lays groundwork for machine-learning device

18.08.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>