Naslov
Serylation in protein biosynthesis: trials, facts and excitements in the last decade

Autori
Weygand-Đurašević, Ivana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
45 Years of molecular biology in Croatia, 50 years of double helix / Ambrimović Ristov, Andreja ; Brozović, Anamaria - Zagreb : Farmaceutsko-biokemijski fakultet Sveučilišta u Zagrebu, 2003, 14-14

Skup
45 Years of molecular biology in Croatia, 50 years of double helix

Mjesto i datum
Zagreb, Hrvatska, 20.11.2003. - 21.11.2003

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
tRNASer ; seryl-tRNA synthetase

Sažetak
Aminoacyl-tRNA synthetases (aaRSs) are ancient proteins that establish the rules of the genetic code through aminoacylation reactions, where a specific amino acid is joined to its cognate tRNA. Each amino acid has its own specific tRNA synthetase, so that a total of twenty enzymes are responsible for all of the aminoacylation reactions. In bacteria and archaea these twenty enzymes are typically encoded by single genes, while in eukaryotes separate genes usually codes for cytoplasmic and mitohondrial forms. The existence of single copy genes is thought to reflect, in part, the result of selective pressure against any gene proliferations that could result in corruption of the code. Genetic code ambiguity can also be caused by misacylation reaction, which is the consequence of the inherent inability of the active site domain to discriminate between closely similar amino acids. This must be either prevented or the error is corrected, usually by the action of appended editing domains. By investigating seryl-tRNA formation in various organisms and cellular compartments, we have observed several exceptions to the standard aminoacylation rules: i) some archaeal species comprise two genes that encode structurally different SerRSs ; ii) in plants, although protein synthesis takes place in three cellular compartments, there are only two genes encoding two seryl-tRNA synthetase isoforms ; iii) accurate seryl-tRNA synthesis in yeast and plants is accomplished via tRNA-assisted optimization of amino acid binding to the enzyme active site. Thus, transient protein:RNA complex activates the cognate amino acid more efficiently and more specifically than the apoenzyme alone, showing that the sequence-specific tRNA:SerRS interactions enhance the accuracy of amino acid discrimination ; iv) peroxin Pex21p was identified as SerRS-interacting protein in Saccharomyces cerevisiae. Besides its main function in peroxisome biogenesis, Pex21p acts as a specific activator of SerRS by increasing the efficiency of aminoacylation. This finding supports the idea that eukaryotic aminoacyl-tRNA synthetases may require protein co-factors.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA