title: Conformational switching in the fungal light sensor Vivid.
abstract: The Neurospora crassa photoreceptor Vivid tunes blue-light responses and modulates gating of the circadian clock. Crystal structures of dark-state and light-state Vivid reveal a light, oxygen, or voltage Per-Arnt-Sim domain with an unusual N-terminal cap region and a loop insertion that accommodates the flavin cofactor. Photoinduced formation of a cystein-flavin adduct drives flavin protonation to induce an N-terminal conformational change. A cysteine-to-serine substitution remote from the flavin adenine dinucleotide binding site decouples conformational switching from the flavin photocycle and prevents Vivid from sending signals in Neurospora. Key elements of this activation mechanism are conserved by other photosensors such as White Collar-1, ZEITLUPE, ENVOY, and flavin-binding, kelch repeat, F-BOX 1 (FKF1).
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Zoltowski
authors.forename: Carsten
authors.initials: C
authors.lastname: Schwerdtfeger
authors.forename: Joanne
authors.initials: J
authors.lastname: Widom
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Loros
authors.forename: Alexandrine M
authors.initials: AM
authors.lastname: Bilwes
authors.forename: Jay C
authors.initials: JC
authors.lastname: Dunlap
authors.forename: Brian R
authors.initials: BR
authors.lastname: Crane
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003624:Darkness; D019281:Dimerization; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009492:Neurospora crassa / Q000737:chemistry*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D005656:Fungal Proteins; C423283:VVD protein, Neurospora crassa; D005182:Flavin-Adenine Dinucleotide