Synthesis of Metalloproteins Involved in Photosynthesis: Plastocyanin and Cytochromes

摘要: The introduction of a metal cofactor broadens the catalytic repertoire protein catalyst by facilitating certain types chemical reactions. chemistry depends upon type coordinating ligands, and also geometry metal-containing active site. Metalloprotein biosynthesis requires 1) mechanisms acquisition transport to sub-cellular compartment where delivery site metalloprotein can occur, 2) coordinate regulation polypeptide synthesis with (for organic cofactors like heme) or assimilation inorganic Md4 cluster). copper-responsive accumulation copper-containing plastocyanin heme-containing cytochrome c6 in Chlamydomonas reinhardtii has served as model for studies metalloproteins metals because simple growth requirements facilitate metabolism. In fully copper-supplemented medium, accumulates C. but Cyt does not. As medium is depleted copper (<×106 Cu/cell), adaptation copper-deficiency are induced. These include degradation plastocyanin, transcriptional activation Cyc6 Cpx1 genes (encoding coprogen oxidase, respectively), induction cupric reductase activity. Studies chloroplast assembly have focused primarily on heme proteins, c-type cytochromes being best studied examples. occurrence distribution genome databases Ccs required maturation suggests that they represent third family components, distinct from c/c1 lyases mammalian fungal mitochondria components identified most proteobacteria plant mitochondria. Approaches analysis other cofactor-containing proteins discussed.