Membrane protein damage and repair: removal and replacement of inactivated 32-kilodalton polypeptides in chloroplast membranes [Chlamydomonas reinhardii]

• Published in: The Journal of cell biology Vol. 99; no. 2; pp. 481 - 485
• Main Authors: Ohad, I, Kyle, D.J, Arntzen, C.J
• Format: Journal Article
• Language: English
• Published: New York, NY Rockefeller University Press 01.08.1984; The Rockefeller University Press
• Subjects: Biological and medical sciences; Cell growth; Cell structures and functions; Cells; Chlamydomonas; Chlamydomonas - metabolism; Chloroplast, photosynthetic membrane and photosynthesis; Chloroplasts; Chloroplasts - metabolism; damage; Electron Transport; Electrons; Fluorescence; Fundamental and applied biological sciences. Psychology; Intracellular Membranes - metabolism; Kinetics; Membrane proteins; Membrane Proteins - isolation & purification; Membrane Proteins - metabolism; membranes; Molecular and cellular biology; Molecular Weight; Peptides - isolation & purification; Photoinhibition; Photosynthesis; Photosynthetic Reaction Center Complex Proteins; Photosystem II Protein Complex; Plant cells; Plant Proteins; polypeptides; proteins; Quinones; repairing; Thylakoids; Membrane protein; Vegetals; Algae; Chlorophycophyta; Chlamydomonas reinhardi; Thylakoid; Herbicide; Renewal; Photosystem 2; Binding protein; Photoinhibition; Electron acceptor; Chloroplast; Thallophyta
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.99.2.481

Incubation of Chlamydomonas reinhardii cells at light levels that are several times more intense than those at which the cells were grown results in a loss of photosystem II function (termed photoinhibition). The loss of activity corresponded to the disappearance from the chloroplast membranes of a lysine-deficient, herbicide-binding protein of 32,000 daltons which is thought to be the apoprotein of the secondary quinone electron acceptor of photosystem II (the QBprotein). In vivo recovery from the damage only occurred following de novo synthesis (replacement) of the chloroplast-encoded QBprotein. We believe that the turnover of this protein is a normal consequence of its enzymatic function in vivo and is a physiological process that is necessary to maintain the photosynthetic integrity of the thylakoid membrane. Photoinhibition occurs when the rate of inactivation and subsequent removal exceeds the rate of resynthesis of the QBprotein.