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Identification of an OPR protein involved in the translation initiation of the PsaB subunit of photosystem I
Author(s) -
Rahire Michèle,
Laroche Fabrice,
Cerutti Lorenzo,
Rochaix JeanDavid
Publication year - 2012
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2012.05111.x
Subject(s) - protein subunit , photosystem ii , photosystem i , identification (biology) , translation (biology) , p700 , chemistry , biology , botany , biochemistry , photosynthesis , messenger rna , gene
Summary Genetic analysis of mutants deficient in the biosynthesis of the photosystem I complex has revealed several nucleus‐encoded factors that act at different post‐transcriptional steps of chloroplast gene expression. Here we have identified and characterized the gene affected in the tab 1‐F15 mutant, which is specifically deficient in the translation of the photosystem I reaction center protein PsaB as the result of a single nucleotide deletion. This gene encodes Tab 1, a 1287 amino acid protein that contains 10 tandem 38–40 amino acid degenerate repeats of the PPPEW/OPR (octatricopeptide repeat) family, first described for the chloroplast translation factor Tbc2. These repeats are involved in the binding of Tab 1 to the 5′‐untranslated region of the psaB mRNA based on gel mobility shift assays. Tab 1 is part of a large family of proteins in Chlamydomonas that are also found in several bacteria and protozoans, but are rare in land plants.