PsbT Polypeptide Is Required for Efficient Repair of Photodamaged Photosystem II Reaction Center

Norikazu Ohnishi, Yuichiro Takahashi

    Research output: Contribution to journalArticlepeer-review

    36 Citations (Scopus)


    PsbT is a small chloroplast-encoded hydrophobic polypeptide associated with the photosystem II (PSII) core complex. A psbT-deficient mutant (ΔpsbT) of the green alga Chlamydomonas reinhardtii grows photoautotrophically, whereas its growth is significantly impaired in strong light. To understand the photosensitivity of ΔpsbT, we have studied the effect of strong illumination on PSII activity and proteins. It is shown that the level of PSII activity and proteins is reduced in the ΔpsbT more significantly than in wild type under strong light. When recovery of the photodamaged PSII is inhibited by a chloroplast protein synthesis inhibitor, the light-induced inactivation and degradation of PSII occur similarly in wild-type and mutant cells. On the contrary, the recovery of PSII activity after partial photoinactivation is remarkably delayed in the ΔpsbT cells, suggesting that PsbT is required for efficient recovery of the photodamaged PSII complex. These results therefore present the first evidence for involvement of this small PSII polypeptide in the recovery process. Partial disintegration of the purified PSII core complex and localization of PSII proteins in the resulting PSII subcore complexes have revealed that PsbT is associated with D1/D2 heterodimer. A possible role of PsbT in the recovery process is discussed.

    Original languageEnglish
    Pages (from-to)33798-33804
    Number of pages7
    JournalJournal of Biological Chemistry
    Issue number36
    Publication statusPublished - Sep 7 2001

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology


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