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
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences