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Abstract
Photosynthetic membranes are typically densely packed with proteins, and this is crucial for their function in efficient trapping of light energy. Despite being crowded with protein, the membranes are fluid systems in which proteins and smaller molecules can diffuse. Fluidity is also crucial for photosynthetic function, as it is essential for biogenesis, electron transport, and protein redistribution for functional regulation. All photosynthetic membranes seem to maintain a delicate balance between crowding, order, and fluidity. How does this work in phototrophic bacteria? In this review, we focus on two types of intensively studied bacterial photosynthetic membranes: the chromatophore membranes of purple bacteria and the thylakoid membranes of cyanobacteria. Both systems are distinct from the plasma membrane, and both have a distinctive protein composition that reflects their specialized roles. Chromatophores are formed from plasma membrane invaginations, while thylakoid membranes appear to be an independent intracellular membrane system. We discuss the techniques that can be applied to study the organization and dynamics of these membrane systems, including electron microscopy techniques, atomic force microscopy, and many variants of fluorescence microscopy. We go on to discuss the insights that havebeen acquired from these techniques, and the role of membrane dynamics in the physiology of photosynthetic membranes. Membrane dynamics on multiple timescales are crucial for membrane function, from electron transport on timescales of microseconds to milliseconds to regulation and biogenesis on timescales of minutes to hours. We emphasize the open questions that remain in the field.
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Affiliation(s)
- Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266003, China
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Kudryashev M, Aktoudianaki A, Dedoglou D, Stahlberg H, Tsiotis G. The ultrastructure of Chlorobaculum tepidum revealed by cryo-electron tomography. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1635-42. [DOI: 10.1016/j.bbabio.2014.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/04/2014] [Accepted: 06/10/2014] [Indexed: 11/28/2022]
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Boekema EJ. Introduction to imaging methods in photosynthesis. PHOTOSYNTHESIS RESEARCH 2009; 102:107-9. [PMID: 19757143 PMCID: PMC2777216 DOI: 10.1007/s11120-009-9488-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 08/10/2009] [Indexed: 05/28/2023]
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