Molecular design of the photosystem II light-harvesting antenna: photosynthesis and photoprotection.
The photosystem II (PSII) light-harvesting system carries out two essential functions, the efficient collection of light energy for photosynthesis, and the regulated dissipation of excitation energy in excess of that which can be used. This dual function requires structural and functional flexibility, in which light-harvesting proteins respond to an external signal, the thylakoid DeltapH, to induce feedback control. This process, referred to as non-photochemical quenching (NPQ) depends upon the xanthophyll cycle and the PsbS protein. In nature, NPQ is heterogeneous in terms of kinetics and capacity, and this adapts photosynthetic systems to the specific dynamic features of the light environment. The molecular features of the thylakoid membrane which may enable this flexibility and plasticity are discussed.
Horton
Peter
P
Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK. p.horton@sheffield.ac.uk
Ruban
Alexander
A
D000222:Adaptation, Physiological; D019143:Evolution, Molecular; D008027:Light; D010788:Photosynthesis / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000502:physiology* / Q000528:radiation effects*; D010940:Plant Proteins / Q000502:physiology; D011487:Protein Conformation; D013045:Species Specificity; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000378:metabolism
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene