Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists clarify structural basis for biosynthesis of mysterious 21st amino acid

13.08.2010
The findings deepen our understanding of protein synthesis and lay the groundwork for advances in protein design.

Researchers at the RIKEN Systems and Structural Biology Center and the University of Tokyo have clarified the structural basis for the biosynthesis of selenocysteine (Sec), an amino acid whose encoding mechanism offers clues about the origins of the genetic alphabet. The findings deepen our understanding of protein synthesis and lay the groundwork for advances in protein design.

One of the most remarkable aspects of translation, the process whereby genetic information is converted into proteins in cells, is its universality: nucleotide triplets (“codons”) encode a set of twenty amino acids that form the building blocks for all living organisms. Selenocysteine, the “21st amino acid” whose antioxidant properties help prevent cellular damage, is a rare exception to this rule. Structurally similar to the amino acid serine (Ser) but with an oxygen atom replaced by the micronutrient selenium (Se), selenocysteine is synthesized through a complex juggling of the cell’s translational machinery whose mechanisms remain poorly understood.

Central to this multi-step process is a Sec-specific transfer RNA (tRNASec) with an unusual structure that enables it to hijack the “stop codon” UGA to allow incorporation of selenocysteine during protein synthesis. In earlier work, the researchers identified features of tRNASec that differentiate it from other tRNA, notably the peculiar structure of a domain called the D-arm, which appeared to act as an identification marker for recognition by the selenocysteine synthesis machinery. This time, the team analyzed the D-arm’s role in the interaction of tRNASec with O-phosphoseryl-tRNA kinase (PSTK), a protein whose selective phosphorylation is essential for selenocysteine encoding.

Using X-ray crystallography, the team showed for the first time that it is the unique structure of the tRNASec D-arm which enables PSTK to distinguish tRNASec from other tRNA. Reported in the August 13th issue of Molecular Cell (online August 12th), the discovery clarifies a pivotal step in selenocysteine biosynthesis, shedding new light on the mysterious 21st amino acid and the elaborate process by which it is created.

For more information, please contact:

Dr. Shigeyuki Yokoyama
RIKEN Systems and Structural Biology Center (SSBC)
Tel: +81-(0)45-503-9196 / Fax: +81-(0)45-503-9195
Ms. Tomoko Ikawa (PI officer)
Global Relations Office
RIKEN
Tel: +81-(0)48-462-1225 / Fax: +81-(0)48-463-3687
Email: koho@riken.jp
Reference:
Shiho Chiba, Yuzuru Itoh, Shun-ichi Sekine and Shigeyuki Yokoyama. Structural Basis for the Major Role of O-Phosphoseryl-tRNA Kinase in the UGA-Specific Encoding of Selenocysteine. Molecular Cell 39: 1-11. August 13, 2010. DOI: 10.1016/j.molcel.2010.07.018

Journal information
Molecular Cell

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>