Function of the stromal processing peptidase in the chloroplast import pathway

Autor: Gayle K. Lamppa, Stefan Richter, Rong Zhong
Rok vydání: 2005
Předmět:
Zdroj: Physiologia Plantarum. 123:362-368
ISSN: 1399-3054
0031-9317
DOI: 10.1111/j.1399-3054.2005.00476.x
Popis: 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.
Databáze: OpenAIRE
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