title: Ultrafast spectroscopy of biological photoreceptors.
abstract: We review recent new insights on reaction dynamics of photoreceptors proteins gained from ultrafast spectroscopy. In Blue Light sensing Using FAD (BLUF) domains, a hydrogen-bond rearrangement around the flavin chromophore proceeds through a radical-pair mechanism, by which light-induced electron and proton transfer from the protein to flavin result in rotation of a conserved glutamine that switches the hydrogen bond network. Femtosecond infrared spectroscopy has shown that in photoactive yellow protein (PYP), breaking of a hydrogen bond that connects the p-coumaric acid chromophore to the backbone is crucial for trans-cis isomerization and successful entry into the photocycle. Furthermore, isomerization reactions of phycocyanobilin in phytochrome and retinal in the rhodopsins have been revealed in detail through application of femtosecond infrared and femtosecond-stimulated Raman spectroscopy.
authors.affiliation: Department of Biophysics, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081HV Amsterdam, The Netherlands. john@nat.vu.nl
authors.forename: John T M
authors.initials: JT
authors.lastname: Kennis
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Groot
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000378:metabolism; D010834:Phytochrome / Q000737:chemistry; D017434:Protein Structure, Tertiary; D012242:Rhodobacter sphaeroides / Q000737:chemistry; D012243:Rhodopsin / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods*; D013055:Spectrophotometry, Infrared / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D046939:Synechocystis / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; C050162:photoactive yellow protein, Bacteria; D010834:Phytochrome; D005182:Flavin-Adenine Dinucleotide; D012243:Rhodopsin