title: Chloroplast-encoded PsbT is required for efficient biogenesis of photosystem II complex in the green alga Chlamydomonas reinhardtii.
abstract: The small hydrophobic polypeptide PsbT is associated with the photosystem II (PSII) reaction center (D1/D2 heterodimer). Here, we report the effect of the deletion of PsbT on the biogenesis of PSII complex during light-induced greening of y-1 mutants of the green alga Chlamydomonas reinhardtii. The y-1 is unable to synthesize chlorophylls in the dark but do so in the light. The dark-grown y-1 cells accumulated no major PSII proteins but a small amount of PsbT. Upon illumination, PsbT was immediately synthesized while chlorophylls, major PSII proteins, and O(2)-evolving activity increased after a 1-h lag. The y-1 cells without PsbT accumulated chlorophylls and PSI protein at a similar rate, whereas the accumulation of PSII complex was specifically retarded during greening. The absence of PsbT did not affect the synthesis of PSII proteins. These results indicate that PsbT is required for the efficient biogenesis of PSII complex.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Ohnishi
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D020418:Algal Proteins / Q000378:metabolism*; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D017353:Gene Deletion; D045332:Photosystem II Protein Complex / Q000096:biosynthesis* / Q000378:metabolism; D013696:Temperature
chemical_list: D020418:Algal Proteins; D045332:Photosystem II Protein Complex; C093489:photosystem II, psbT subunit