The LOV2 domain of phototropin: a reversible photochromic switch.
Light, oxygen, or voltage (LOV) domains constitute a new class of photoreceptor proteins that are sensitive to blue light through a noncovalently bound flavin chromophore. Blue-light absorption by the LOV2 domain initiates a photochemical reaction that results in formation of a long-lived covalent adduct between a cysteine and the flavin cofactor. We have applied ultrafast spectroscopy on the photoaccumulated covalent adduct state of LOV2 and find that, upon absorption of a near-UV photon by the adduct state, the covalent bond between the flavin and the cysteine is broken and the blue-light-sensitive ground state is regained on an ultrafast time scale of 100 ps. We thus demonstrate that the LOV2 domain is a reversible photochromic switch, which can be activated by blue light and deactivated by near-UV light.
Kennis
John T M
JT
Department of Biophysics, Faculty of Sciences, Vrije Universiteit, 1081HV Amsterdam, The Netherlands. j.kennis@few.vu.nl
van Stokkum
Ivo H M
IH
Crosson
Sean
S
Gauden
Magdalena
M
Moffat
Keith
K
van Grondelle
Rienk
R
D035681:Adiantum / Q000737:chemistry; D056931:Cryptochromes; D003545:Cysteine / Q000737:chemistry; D029721:Drosophila Proteins; D005136:Eye Proteins; D005415:Flavins / Q000737:chemistry; D005420:Flavoproteins / Q000737:chemistry*; D017956:Photoreceptor Cells, Invertebrate; D010940:Plant Proteins / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D043562:Receptors, G-Protein-Coupled; D013056:Spectrophotometry, Ultraviolet
D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005415:Flavins; D005420:Flavoproteins; D010940:Plant Proteins; D043562:Receptors, G-Protein-Coupled; C119828:cry protein, Drosophila; D003545:Cysteine