Dresden 2014 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 5: Protein structure and dynamics I

BP 5.3: Vortrag

Montag, 31. März 2014, 15:30–15:45, ZEU 250

Electrochromic shift calculations exhibit the light-activation mechanism of BLUF photoreceptors — •Florimond Collette, Marcel Schmidt am Busch, and Thomas Renger — Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria

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] S. Masuda, Plant Cell Physiol. 54, 171 (2013).

[2] S. Anderson et al., Biochemistry 44, 7998 (2005).

[3] A. Jung et al., Proc. Natl. Acad. Sci. USA 102, 12350 (2005).

[4] F. Collette et al., submitted.