Electrochromic shift calculations exhibit the light-activation mechanism of BLUF photoreceptors

Description

The photoreceptor family named BLUF, short for ‘sensors of blue-light using flavin adenine dinucleotide (FAD)’, is involved in a variety of important physiological reactions like phototaxis, photosynthetic gene regulation and virulence. Upon illumination with blue light, the photoreceptor switches into a light-adapted signaling state, with a measurable 10 to 15 nm redshift of the absorption maximum. The spectroscopic shift is explained by an alteration in the hydrogen bonding pattern surrounding the chromophore [1]. Two opposite molecular models exist. One model is supported by the majority of crystallographic studies [2], whereas the second is favored by most spectroscopical works [3]. Within the framework of a quantum chemical/electrostatic calculation scheme, we estimated absorption shifts of the flavin chromophore for a series of site-directed mutants and different BLUF proteins. Our calculations accurately reproduce a series of spectroscopic data and provide compelling evidence for the model supported by the majority of crystallographic studies [4]. [1] Masuda, S., Plant Cell Physiol. 54, 171 (2013). [2] Anderson, S. et al., Biochemistry 44, 7998 (2005). [3] Jung, A. et al., Proc. Natl. Acad. Sci. U.S.A. 102, 12350 (2005). [4] Collette, F. et al., J. Phys. Chem. B 118, 11109 (2014).

Period	01 Feb 2014
Event title	XVI. Annual Linz Winter Workshop 2014
Event type	Conference
Location	AustriaShow on map