[Chloroplast Deg proteases].

For some chloroplast proteases ATP binding and hydrolysis is not necessary for their catalytic activity, most probably because even strongly unfolded substrates may penetrate their catalytic chamber. Deg1, 2, 5 and 8 are the best known of Arabidopsis thaliana ATP- independent chloroplast proteases, encoded by orthologues of genes coding for DegP, DegQ and DegS proteases of Escherichia coli. Current awareness in the area of structure and functions of chloroplast Degs is much more limited vs the one about their bacterial counterparts.

[ATP-dependent FtsH and Lon chloroplast proteases].

Arabidopsis thaliana proteome contains 667 proteases; some tens of them are chloroplast-targeted proteins, encoded by genes orthologous to the ones coding for bacterial proteolytic enzymes. It is thought that chloroplast proteases are involved in chloroplasts' proteins turnover and quality control (maturation of nucleus-encoded proteins and removal of nonfunctional ones). Some ATP-dependent chloroplast proteases belonging to FtsH family (especially FtsH2 and FtsH5) are considered to be involved in numerous aspects of chloroplast and whole plant maintenance under non-stressing as well as stressing conditions.