Mechanism of selenocysteine incorporation on the ribosome

• Antragsteller: Dr. Kirill Gromadski
• Fachliche Zuordnung: Biochemie
• Förderung: Förderung von 2005 bis 2008
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 20967925

The insertion of selenocysteine into proteins in bacteria requires a UGA codon in the open reading frame of mRNA, a specific mRNA hairpin structure (SECIS element), tRNASec, and a specialized elongation factor termed SelB. The molecular mechanism of SelB function on the ribosome and the sequence of events during selenocysteine incorporation are not known so far. The present project aims at understanding the molecular mechanisms of setenocysteine incorporation in bacteria by using biochemical and biophysical in vitro techniques. We plan to establish the experimental system to study the interactions between SelB, GTP, Sec-tRNASec and the ribosome programmed with mRNA containing a SECIS element using rapid kinetics and biophysical techniques. The mechanism of GTPase activation of SelB in the ternary complex and its regulation by the mRNA recognition elements, i.e. UGA codon and SECIS, will be investigated. Reaction intermediates will be identified and the kinetics of the transitions between the intermediates will be determined. The results are expected to shed light on the molecular pathway of selenocysteine incorporation and on the mechanisms of substrate recognition and selection during translation in general.

• DFG-Verfahren: Forschungsstipendien
• Gastgeberin: Professorin Dr. Marina V. Rodnina