Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 56: Protein Structure and Dynamics

BP 56.4: Talk

Thursday, March 23, 2017, 16:00–16:15, SCH A251

Elucidation of light-induced structural changes of aureochrome by small-angle X-ray scattering — •Saskia Bannister, Elena Herman, Thomas Hellweg, and Tilman Kottke — Bielefeld University, Germany

Aureochromes function as blue-light-regulated transcription factors in algae. Their basic region leucine zipper (bZIP) effector domain binds DNA with a specific sequence while a light-, oxygen-, or voltage-sensitive (LOV) domain acts as the C-terminal sensor. Due to this unusual arrangement of sensor and effector, aureochromes are interesting for studying their mechanism and for the engineering of new synthetic optogenetic tools.

We are applying small-angle X-ray scattering (SAXS) to resolve the solution structure of the full-length receptor and the monomeric LOV domain. However, SAXS on photoreceptors is challenging. First, dark conditions need to be absolutely strict to avoid conversion of the highly sensitive receptor. Second, the analysis under illumination needs to ensure full conversion. Therefore we are establishing SAXS experiments under rigorous control of light and simultaneous UV/Vis monitoring on an in-house setup. First results from SAXS measurements on LOV under true dark conditions are presented. Experiments on the full-length aureochrome are currently pursued.

Banerjee, A., Herman, E., Serif, M., Maestre-Reyna, M., Hepp, S., Pokorny, R., Kroth, P. G., Essen, L.-O., Kottke, T. (2016), Nucleic Acids Res. 44(12), 5957-5970.

Herman, E., Kottke, T. (2015), Biochemistry 54, 1484-1492.