title: Mechanisms underlying carotenoid absorption in oxygenic photosynthetic proteins.
abstract: The electronic properties of carotenoid molecules underlie their multiple functions throughout biology, and tuning of these properties by their in vivo locus is of vital importance in a number of cases. This is exemplified by photosynthetic carotenoids, which perform both light-harvesting and photoprotective roles essential to the photosynthetic process. However, despite a large number of scientific studies performed in this field, the mechanism(s) used to modulate the electronic properties of carotenoids remain elusive. We have chosen two specific cases, the two β-carotene molecules in photosystem II reaction centers and the two luteins in the major photosystem II light-harvesting complex, to investigate how such a tuning of their electronic structure may occur. Indeed, in each case, identical molecular species in the same protein are seen to exhibit different electronic properties (most notably, shifted absorption peaks). We assess which molecular parameters are responsible for this in vivo tuning process and attempt to assign it to specific molecular events imposed by their binding pockets.
authors.affiliation: Institut de Biologie et de Technologies de Saclay, UMR 8221 CNRS, Université Paris Sud, Commissariat à l'Energie Atomique Saclay, 91191 Gif-sur-Yvette, France.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Mendes-Pinto
authors.forename: Denise
authors.initials: D
authors.lastname: Galzerano
authors.forename: Alison
authors.initials: A
authors.lastname: Telfer
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Pascal
authors.forename: Bruno
authors.initials: B
authors.lastname: Robert
authors.forename: Cristian
authors.initials: C
authors.lastname: Ilioaia
mesh_terms: D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry*; D014975:Lutein / Q000737:chemistry*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman; D018724:Spinacia oleracea / Q000201:enzymology; D013696:Temperature; D019207:beta Carotene / Q000737:chemistry*
chemical_list: D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D012997:Solvents; D019207:beta Carotene; D014975:Lutein
keywords: Carotenoid; Electronic Absorption; LHCII; Lutein; Photosynthesis; Photosystem II; Raman Spectroscopy; Spectroscopy; β-Carotene