Sublocalization of Cytochrome b6f Complexes in Photosynthetic Membranes. (July 2017)

• Record Type: Journal Article
• Authors: Kirchhoff, Helmut; Li, Meng; Puthiyaveetil, Sujith
• Is Part Of: Trends in plant science. Volume 22:Number 7(2017)
• Page Start: 574
• Page End: 582
• Publication Date: 2017-07
• Subjects: cytochrome b6f complex -- grana -- photosynthesis -- thylakoid membrane; Botany -- Periodicals; Botanique -- Périodiques; Botany; Periodicals; 580.5
• DOI: 10.1016/j.tplants.2017.04.004
• Languages: English
• ISSNs: 1360-1385

Abstract

Abstract : It is well established that the majority of energy-converting photosynthetic protein complexes in plant thylakoid membrane are nonhomogenously distributed between stacked and unstacked membrane regions. Yet, the sublocalization of the central cytochrome b 6 f complex remains controversial. We present a structural model that explains the variation in cytochrome b 6 f sublocalization data. Small changes in the distance between adjacent membranes in stacked grana regions either allow or restrict access of cytochrome b 6 f complexes to grana. If the width of the gap falls below a certain threshold, then the steric hindrance prevents cytochrome b 6 f access to grana. Evidence is presented that the width of stromal gap is variable, demonstrating that the postulated mechanism can regulate the lateral distribution of the cytochrome b 6 f complexes. Trends: Recent advances in ultrastructural analysis (electron microscopy) provide precise information on the dimension of the photosynthetic thylakoid membrane. It becomes clear that the geometrical features of the thylakoid membrane, in particular that of the stacked grana membranes, have a deep significance for the functionality, regulation, and maintenance of the energy-converting photosynthetic machinery. Determination of the lateral distribution of photosynthetic complexes between stacked and unstacked membrane regions and quantification of high- and low-abundant proteins involved in the regulation, biogenesis, and turnover of the photosynthetic apparatus allow unraveling of the mechanistic basis of energy-conversion processes.