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Function of the stromal processing peptidase in the chloroplast import pathway
Author(s) -
Richter Stefan,
Zhong Rong,
Lamppa Gayle
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.1399-3054.2005.00476.x
Subject(s) - organelle , transit peptide , chloroplast , biogenesis , biology , proteases , biochemistry , signal peptide , microbiology and biotechnology , signal peptidase , organelle biogenesis , cleavage (geology) , cytosol , enzyme , peptide sequence , plastid , gene , paleontology , fracture (geology)
Chloroplast biogenesis depends on the import of a large diversity of proteins synthesized as precursors in the cytosol. The N‐terminal targeting signal, the transit peptide, is proteolytically removed as proteins enter the organelle by a stromal processing peptidase (SPP) in a regulated series of steps. SPP contains a signature HXXEH zinc‐binding motif found in members of the M16 metallopeptidase family, which includes, most notably, the mitochondrial processing peptidase. Here we discuss: (i) the broad range of substrates cleaved by SPP, yielding mature proteins for the numerous biosynthetic pathways of the organelle; (ii) the structural features that reside in both SPP and the transit peptide that determine the high specificity of precursor cleavage; (iii) the downregulation of SPP in vivo which shows that it is essential for plant survival; and (iv) the relationship between SPP from higher plants and proteases in several lower eukaryotes and the cyanobacteria.