Heterologous expression of the phytochelatin synthetase CaPCS2 confers resistance to various stress factors in Esche-richia coli.. CaPCS2 updated seqence

Phytochelatins (PCs) are cysteine-rich small peptides, enzymatically synthesized from reduced glutathione (GSH) by cytosolic enzyme phytochelatin synthase (PCS). The ORF (open reading frame) of the phytochelatin synthetase CaPCS2 gene from the micro-algae Chlamydomonas acidophila, was heterologously expressed in Escherichia coli strain DH5, to analyse its role in protection against various abiotic agents that cause cellu-lar stress. The transformed E. coli strain showed increased tolerance to exposure to dif-ferent heavy metals and arsenic, as well as to acidic pH and exposure to UVB, salt or perchlorate. In addition to metal detoxification activity, new functions have also been reported for PCS and PCs. According to the results obtained in this work, heterologous expression of CaPCS2 in E. coli provides protection against oxidative stress produced by metals and exposure to different ROS-inducing agents. However, the function of this PCS is not related to heavy metal bioaccumulation.