Pitt, a novel tetratricopeptide repeat protein involved in light-dependent chlorophyll biosynthesis and thylakoid membrane biogenesis in Synechocystis sp. PCC 6803.
Biogenesis of photosynthetic pigment/protein complexes is a highly regulated process that requires various assisting factors. Here, we report on the molecular analysis of the Pitt gene (slr1644) from the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803) that encodes a membrane-bound tetratricopeptide repeat (TPR) protein of formerly unknown function. Targeted inactivation of Pitt affected photosynthetic performance and light-dependent chlorophyll synthesis. Yeast two-hybrid analyses and native PAGE strongly suggest a complex formation between Pitt and the light-dependent protochlorophyllide oxidoreductase (POR). Consistently, POR levels are approximately threefold reduced in the pitt insertion mutant. The membrane sublocalization of Pitt was found to be dependent on the presence of the periplasmic photosystem II (PSII) biogenesis factor PratA, supporting the idea that Pitt is involved in the early steps of photosynthetic pigment/protein complex formation.
Molekulare Pflanzenwissenschaften, Biozentrum LMU München, Grobetahaderner Str. 2-4, 82152 Planegg-Martinsried, Germany.
Marco
M
Schottkowski
Janina
J
Ratke
Ulrike
U
Oster
Marc
M
Nowaczyk
Jörg
J
Nickelsen
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D002734:Chlorophyll / Q000235:genetics / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000201:enzymology / Q000235:genetics; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D046939:Synechocystis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D020524:Thylakoids / Q000235:genetics / Q000378:metabolism
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase