engleski

Maize mitochondrial seryl-tRNA synthetase recorgnizes Escherichia coli tRNASer in vivo and in vitro

Towards our goal to analyze the structure/function relationship among cytoplasmic and organellar seryl-tRNA synthetases (SerRS), we have characterized a Zea mays cDNA (SerZMo) encoding a protein with significant homology to prokaryotic SerRS enzymes. The alignment has also revealed that the clone probably lacks the 5'end sequence coding for the part of the organellar targeting signal. In order to verify the functional identity of SerZMo, an expression cassette, containing the region that codes for putative mature protein, was constructed. The construct complemented temperature-sensitive mutation in Escherichia coli serS gene in vivo. Mature SerZMo protein overexpressed in E. coli, efficiently aminoacylated bacterial tRNASer in vitro, while yeast tRNA was a poor substrate. These data identify SerZMo as an organellar maize seryl-tRNA synthetase, the first plant organellar SerRS to be cloned.

cDNA cloning ; gene expression ; in vivo complementation ; seryl-tRNA synthetases ; Zea mays

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