The β-scaffold of the LOV domain of the Brucella light activated histidine kinase is a key element for signal transduction

RINALDI J.; GALLO M.; KLINKE S.; PARIS G.; BONOMI H.R.; BOGOMOLNI R.; CICERO D.O.; GOLDBAUM F.A.

Galveston, Texas

Conferencia; Gordon Research Conference: Photosensory Receptors & Signal Transduction; 2012

Light-oxygen-voltage (LOV) domains are blue light activated signaling modules present in a wide range of sensory proteins. Among them, the histidine kinases are the largest group in bacteria (LOV-HK). Light modulates the virulence of the pathogenic bacteria Brucella abortus through LOV-HK. While the full length LOV-HK and the LOV domain containing the Jα-helix remain activated upon illumination without recovering the basal state, the isolated LOV domain core slowly returns to the dark state. We have characterized by X-ray crystallography and solution NMR spectroscopy the structure of the LOV domain of LOV-HK in the dark state and explored its light induced conformational changes. This is the first structural study of a LOV domain from a histidine kinase. The domain dimerizes through the β-scaffold in an antiparallel way. Our results point to the β-scaffold as a key element in the light activation, validating a conserved structural basis for light-tosignal propagation in LOV proteins.