engleski

C-terminal extension of yeast SerRS has important role in tRNA binding and protein- protein interactions

Aminoacyl-tRNA synthetases are essential enzymes that catalyze the formation of aminoacyl-tRNA. Using two-hybrid system, yeast peroxin Pex21p was identified as a protein that specifically interacts with seryl-tRNA synthetase. In order to map SerRS/Pex21p interactive domains, several deletion mutants of SerRS have been produced. The interaction with peroxin was almost entirely lost after deleting positively charged C-terminal peptide of SerRS, which characterizes all eukaryotic seryl-tRNA synthetases. Pex21p is known to be involved in peroxisome biogenesis, but apparently acts as specific activator of SerRS by increasing the efficiency of aminoacylation. Using electrophoretic techniques it was shown that deletion mutant lacking C-terminal extension has impaired ability to bind tRNA. Deletion mutant can interact with tRNA but complex produced has significantly lower stability compared to wild-type complex. In conclusion, C-terminal extension of yeast SerRS functions both as cofactor-binding domain and as auxiliary tRNA-binding domain. Those macromolecular interactions seem to be important for the serylation efficiency.

tRNASer ; seryl-tRAN synthetase ; peroxin

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