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FtsH proteases in chloroplasts and cyanobacteria
Author(s) -
Adam Zach,
Zaltsman Adi,
SinvanyVillalobo Galit,
Sakamoto Wataru
Publication year - 2005
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2004.00436.x
Subject(s) - thylakoid , chloroplast , biology , arabidopsis , aaa proteins , biochemistry , proteases , arabidopsis thaliana , atpase , synechocystis , photoinhibition , mutant , microbiology and biotechnology , gene , photosystem ii , enzyme , photosynthesis
FtsH is a membrane‐bound ATP‐dependent metalloprotease complex found in prokaryotes and organelles of eukaryotic cells. It consists of one or two trans ‐membrane helices at its amino‐terminus, a highly conserved ATPase domain, which relates it to the AAA protein family, and a zinc‐binding domain towards its carboxy‐terminus that serves as the proteolytic site. Most bacteria contain a single FtsH gene, but the cyanobacterium Synechocystis has four. The Arabidopsis thaliana genome contains 12 genes encoding FtsH proteins, nine of them can be targeted to chloroplasts, whereas the other three are mitochondrial. Chloroplast FtsH protease is located in the thylakoid membrane, where it forms complexes, most likely hexamers, whose ATPase and proteolytic domains are exposed to the stroma. It is involved in the degradation of the D1 protein of photosystem II reaction centre during its repair from photoinhibition, as well as in the degradation of unassembled proteins in the thylakoid and the stroma. In Arabidopsis , FtsH2 is the most abundant isomer, followed by FtsH5, 8 and 1. This hierarchy is well reflected in the severity of the variegated phenotype of mutants in these genes.