title: Engineering a pH-Regulated Switch in the Major Light-Harvesting Complex of Plants (LHCII): Proof of Principle.
abstract: Under excess light, photosynthetic organisms employ feedback mechanisms to avoid photodamage. Photoprotection is triggered by acidification of the lumen of the photosynthetic membrane following saturation of the metabolic activity. A low pH triggers thermal dissipation of excess absorbed energy by the light-harvesting complexes (LHCs). LHCs are not able to sense pH variations, and their switch to a dissipative mode depends on stress-related proteins and allosteric cofactors. In green algae the trigger is the pigment-protein complex LHCSR3. Its C-terminus is responsible for a pH-driven conformational change from a light-harvesting to a quenched state. Here, we show that by replacing the C-terminus of the main LHC of plants with that of LHCSR3, it is possible to regulate its excited-state lifetime solely via protonation, demonstrating that the protein template of LHCs can be modified to activate reversible quenching mechanisms independent of external cofactors and triggers.
authors.affiliation: Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Liguori
authors.affiliation: Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Alberto
authors.initials: A
authors.lastname: Natali
authors.affiliation: Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Roberta
authors.initials: R
authors.lastname: Croce
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D001665:Binding Sites; D016825:Chlamydomonas reinhardtii / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005818:Genetic Engineering / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D010788:Photosynthesis / Q000502:physiology*; D010860:Pigments, Biological / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D054730:Protein Interaction Domains and Motifs; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013816:Thermodynamics; D020524:Thylakoids / Q000502:physiology / Q000528:radiation effects; D019076:Transgenes
chemical_list: D045342:Light-Harvesting Protein Complexes; D010860:Pigments, Biological; D011994:Recombinant Proteins