IDENTIFICATION OF A CHLOROPLAST-ENCODED SECA GENE HOMOLOG IN A CHROMOPHYTIC ALGA - POSSIBLE ROLE IN CHLOROPLAST PROTEIN TRANSLOCATION

SecA is one of seven Sec proteins that comprise the prokaryotic protein translocation apparatus. A chloroplast-encoded secA gene has been identified from the unicellular chromophytic alga Pavlova lutherii. The gene predicts a protein that is related to the SecA proteins of Escherichia coli and Bacillus subtilis. The presence of secA, as well as the previously described sec Y and hsp 70 genes, on the chloroplast genome of P. lutherii suggests that this eukaryotic organism utilises protein translocation mechanisms similar to those of bacterial cells.