Light-induced subunit dissociation by a light-oxygen-voltage domain photoreceptor from Rhodobacter sphaeroides.

摘要: Light-oxygen-voltage (LOV) domains bind a flavin chromophore to serve as blue light sensors in wide range of eukaryotic and prokaryotic proteins. LOV are associated with variable effector domain or separate protein signaling partner execute variety functions that include regulation kinases, generation anti-sigma factor antagonists, circadian clocks. Here we present the crystal structure, photocycle kinetics, association properties, spectroscopic features full-length from Rhodobacter sphaeroides (RsLOV). RsLOV exhibits N- C-terminal helical extensions form an unusual bundle at its dimer interface some resemblance transducer sensory rhodopsin II. The light-induced conformational changes revealed comparison light- dark-state structures support shared mechanism proteins originates formation flavin-cysteinyl photoadduct. Adduct disrupts hydrogen bonding active site propagates structural through core extensions. Single-residue variants alter photoadduct lifetimes induce perturb oligomeric state. Size exclusion chromatography, multiangle scattering, small-angle X-ray cross-linking studies indicate dimerizes dark but, upon excitation, dissociates into monomers. This switch state may prove be useful for engineering molecular associations controlled cellular settings.