Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Structure of RNAi complex now crystal clear

21.06.2012
Researchers at the Whitehead Institute and Memorial Sloan-Kettering Cancer Center have defined and analyzed the crystal structure of a yeast Argonaute protein bound to RNA.

This complex plays a key role in the RNA interference (RNAi) pathway that silences gene expression. Describing the molecular structure of a eukaryotic Argonaute protein has been a goal of the RNAi field for close to a decade.

"You can learn a lot from biochemical experiments, but to more fully understand a protein like Argonaute, it's useful to know where all of the atoms are and which amino acids are playing important roles," says Whitehead Institute Member David Bartel, who is also an MIT professor of biology and a Howard Hughes Medical Institute (HHMI) investigator. "Learning the Argonaute crystal structure is an important step in understanding the RNAi biochemical pathway and will be the basis for many future experiments."

The yeast Argonaute structure is described in the June 21st print issue of Nature.

In humans and most other eukaryotes, the RNAi pathway can reduce cellular protein production by reducing the proteins' RNA templates. By exploiting this pathway, scientists are able to knock down the expression of specific proteins and thereby determine their roles within the cell or organism. The RNAi pathway has also been of considerable interest for the treatment of human disease.

RNAi depends on two proteins, Dicer and Argonaute. Dicer recognizes double-stranded RNA (dsRNA), latches onto it, and chops it into pieces 21-23 nucleotides long. Argonaute recognizes the dsRNA bits, discards one strand, and uses the other as a guide. When a single-stranded RNA matches the guide RNA's sequence, Argonaute cleaves the targeted RNA, thereby preventing it from serving as a template for protein production.

To determine the structure of Argonaute, Bartel and graduate student David Weinberg partnered with Kotaro Nakanishi in Dinshaw Patel's lab at Sloan-Kettering. Although the team expected to solve the structure of Argonaute alone, they were surprised to find that the protein came along with small bits of RNA that were also observed in the structure. The incorporation of these RNAs had switched the protein into an activated state that contained a four-component active site, the identification of which solved a longstanding mystery of what constituted the "missing" fourth component. With the structure of this complex in hand, scientists now have a better understanding for how it works.

"Seeing the crystal structure of a eukaryotic Argonaute for the first time was very exciting—it's such a large protein with a complicated topology and many moving parts," says Weinberg. "It's a really impressive molecular machine."

This work was supported by National Institutes of Health (NIH), the Human Frontier Science Program, the Japan Society for the Promotion of Science, and the National Science Foundation (NSF).

Written by Nicole Giese Rura

David Bartel is a Member at Whitehead Institute for Biomedical Research, where his laboratory is located and all his research is conducted. He is also a Howard Hughes Medical Institute Investigator and a professor of biology at Massachusetts Institute of Technology.

Full Citation:

"Structure of yeast Argonaute with guide RNA"

Nature. June 21, 2012.

Kotaro Nakanishi (1,4), David E. Weinberg (2,3,4), David P. Bartel (2,3) & Dinshaw J. Patel (1).

1. Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
2. Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA
3. Howard Hughes Medical Institute and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

4. These authors contributed equally to this work.

Nicole Giese Rura | EurekAlert!
Further information:
http://www.wi.mit.edu

More articles from Life Sciences:

nachricht How a mutation on the novel coronavirus has come to dominate the globe
06.07.2020 | La Jolla Institute for Immunology

nachricht Order from noise: how randomness and collective dynamics define a stem cell
06.07.2020 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

 
Latest News

Protective antibodies identified for rare, polio-like disease in children

06.07.2020 | Health and Medicine

How a mutation on the novel coronavirus has come to dominate the globe

06.07.2020 | Life Sciences

Order from noise: how randomness and collective dynamics define a stem cell

06.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>