Photosynthetic acclimation: structural reorganisation of light harvesting antenna--role of redox-dependent phosphorylation of major and minor chlorophyll a/b binding proteins.
In order to carry out photosynthesis, plants and algae rely on the co-operative interaction of two photosystems: photosystem I and photosystem II. For maximum efficiency, each photosystem should absorb the same amount of light. To achieve this, plants and green algae have a mobile pool of chlorophyll a/b-binding proteins that can switch between being light-harvesting antenna for photosystem I or photosystem II, in order to maintain an optimal excitation balance. This switch, termed state transitions, involves the reversible phosphorylation of the mobile chlorophyll a/b-binding proteins, which is regulated by the redox state of the plastoquinone-mediating electron transfer between photosystem I and photosystem II. In this review, we will present the data supporting the function of redox-dependent phosphorylation of the major and minor chlorophyll a/b-binding proteins by the specific thylakoid-bound kinases (Stt7, STN7, TAKs) providing a molecular switch for the structural remodelling of the light-harvesting complexes during state transitions. We will also overview the latest X-ray crystallographic and electron microscopy-derived models for structural re-arrangement of the light-harvesting antenna during State 1-to-State 2 transition, in which the minor chlorophyll a/b-binding protein, CP29, and the mobile light-harvesting complex II trimer detach from the light-harvesting complex II-photosystem II supercomplex and associate with the photosystem I core in the vicinity of the PsaH/L/O/P domain.
Kargul
Joanna
J
Wolfson Laboratories, Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, UK.
Barber
James
J
D000064:Acclimatization; D020418:Algal Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry*; D008854:Microscopy, Electron; D010084:Oxidation-Reduction; D010766:Phosphorylation; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000737:chemistry*; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation
D020418:Algal Proteins; D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010940:Plant Proteins