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HCF153, a novel nuclear‐encoded factor necessary during a post‐translational step in biogenesis of the cytochrome b 6 f complex
Author(s) -
Lennartz Katja,
Bossmann Sabine,
Westhoff Peter,
Bechtold Nicole,
Meierhoff Karin
Publication year - 2006
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.2005.02605.x
Subject(s) - biology , cytochrome f , biogenesis , cytochrome b6f complex , mutant , cytochrome b , protein subunit , fusion protein , cytochrome , cytochrome c1 , biochemistry , cytochrome c , chloroplast , microbiology and biotechnology , thylakoid , coenzyme q – cytochrome c reductase , gene , mitochondrion , mitochondrial dna , recombinant dna , enzyme
Summary We have isolated the nuclear photosynthetic mutant hcf153 which shows reduced accumulation of the cytochrome b 6 f complex. The levels and processing patterns of the RNAs encoding the cytochrome b 6 f subunits are unaltered in the mutant. In vivo protein labeling experiments and analysis of polysome association revealed normal synthesis of the large chloroplast‐encoded cytochrome b 6 f subunits. The mutation resulted from a T‐DNA insertion and the affected nuclear gene was cloned. HCF153 encodes a 15 kDa protein containing a chloroplast transit peptide. Sequence similarity searches revealed that the protein is restricted to higher plants. A HCF153–Protein A fusion construct introduced into hcf153 mutant plants was able to substitute the function of the wild‐type protein. Fractionation of intact chloroplasts from these transgenic plants suggests that most or all of the fusion protein is tightly associated with the thylakoid membrane. Our data show that the identified factor is a novel protein that could be involved in a post‐translational step during biogenesis of the cytochrome b 6 f complex. It is also possible that HCF153 is necessary for translation of one of the very small subunits of the cytochrome b 6 f complex.