CCH — Arabidopsis thaliana

Summary

AT5G13630 (CCH, also known as GUN5) encodes the H subunit of magnesium chelatase, a protein with magnesium chelatase activity (EC 6.6.1.1) that also exhibits protein-N-terminal asparagine amidohydrolase activity, superoxide dismutase copper carrier activity, and calmodulin binding. The gene is associated with tetrapyrrole and chlorophyll biosynthesis, plastid gene expression, and retrograde signaling. CCH is linked to drought sensitivity, water use efficiency, seed yield, biomass yield, leaf chlorosis, submergence tolerance, and germination rate. It is also associated with chloroplast development, stomatal movement, freezing tolerance, and defense responses. The protein localizes to the chloroplast inner membrane, thylakoid, and envelope, and is associated with abscisic acid-mediated signaling. Studies of related genes in other species link the family to fruit ripening, carotenoid content, and iron deficiency tolerance.