Proteomic amino-termini profiling reveals targeting information for protein import into complex plastids.

In organisms with complex plastids acquired by secondary endosymbiosis from a photosynthetic eukaryote, the majority of plastid proteins are nuclear-encoded, translated on cytoplasmic ribosomes, and guided across four membranes by a bipartite targeting sequence. In-depth understanding of this vital...

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Podrobná bibliografie
Hlavní autoři: Pitter F Huesgen, Meriem Alami, Philipp F Lange, Leonard J Foster, Wolfgang P Schröder, Christopher M Overall, Beverley R Green
Médium: Článek
Jazyk:English
Vydáno: Public Library of Science (PLoS) 2013-01-01
Edice:PLoS ONE
On-line přístup:http://europepmc.org/articles/PMC3774753?pdf=render
Popis
Shrnutí:In organisms with complex plastids acquired by secondary endosymbiosis from a photosynthetic eukaryote, the majority of plastid proteins are nuclear-encoded, translated on cytoplasmic ribosomes, and guided across four membranes by a bipartite targeting sequence. In-depth understanding of this vital import process has been impeded by a lack of information about the transit peptide part of this sequence, which mediates transport across the inner three membranes. We determined the mature N-termini of hundreds of proteins from the model diatom Thalassiosira pseudonana, revealing extensive N-terminal modification by acetylation and proteolytic processing in both cytosol and plastid. We identified 63 mature N-termini of nucleus-encoded plastid proteins, deduced their complete transit peptide sequences, determined a consensus motif for their cleavage by the stromal processing peptidase, and found evidence for subsequent processing by a plastid methionine aminopeptidase. The cleavage motif differs from that of higher plants, but is shared with other eukaryotes with complex plastids.
ISSN:1932-6203