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N‐degron specificity of chloroplast ClpS1 in plants
Author(s) -
Montandon Cyrille,
Dougan David A.,
van Wijk Klaas J.
Publication year - 2019
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.13378
Subject(s) - degron , protease , biochemistry , chemistry , biology , chloroplast , microbiology and biotechnology , enzyme , gene , ubiquitin ligase , ubiquitin
The prokaryotic N‐degron pathway depends on the Clp chaperone‐protease system and the ClpS adaptor for recognition of N‐degron bearing substrates. Plant chloroplasts contain a diversified Clp protease, including the ClpS homolog ClpS1. Several candidate ClpS1 substrates have been identified, but the N‐degron specificity is unclear. Here, we employed in vitro ClpS1 affinity assays using eight N‐degron green fluorescence protein reporters containing either F, Y, L, W, I, or R in the N‐terminal position. This demonstrated that ClpS1 has a restricted N‐degron specificity, recognizing proteins bearing an N‐terminal F or W, only weakly recognizing L, but not recognizing Y or I. This affinity is dependent on two conserved residues in the ClpS1 binding pocket and is sensitive to FR dipeptide competition, suggesting a unique chloroplast N‐degron pathway.