The relevance of protein dynamics for light-signal sensation and protein folding

General ILL Seminar

Organised by College 8

Tuesday 22 January, 11h00

Seminar room 36, Science Building

The relevance of protein dynamics for light-signal sensation and protein folding

Dr. Andreas Stadler

Jülich Centre for Neutron Science JCNS and Institute for Complex Systems ICS, Forschungszentrum Jülich GmbH, Germany

The ability to respond to various environmental stimuli is a crucial ability of biological organisms. Light signal sensation and transduction, for instance, are important biological processes that allow organisms to respond to external stimuli. In recent work we have investigated structural and dynamical changes of a light-sensitive photoreceptor protein in response to light-illumination (1,2). In my presentation, I will present recent neutron spectroscopy and small-angle X-ray scattering experiments, and I will demonstrate how molecular dynamics and protein flexibility are required for light signal transduction of that photoreceptor. In particular, we could demonstrate that end regions of the photoreceptor protein change flexibility as response to light illumination. Hence, changes of protein flexibility are needed for light signal transduction.

In the second part of my talk I will speak about polymer-like properties of the intrinsically disordered myelin basic protein and the unfolded bovine serum albumin (BSA) (3,4,5). Using neutron spin-echo spectroscopy (NSE) we observed a high internal flexibility of those flexible proteins. Internal motions measured by NSE were described using the Zimm model including internal friction (ZIF), which is an extension of the classical Zimm theory used for the interpretations of the dynamics of polymers in solution. Internal friction is due to interactions within the protein chain and due to protein-solvent interactions depending on the quality of the solvent and on the structural expansion of the protein. Disulphide bonds that act as cross-links in denatured BSA have a major impact on internal dynamics as well resulting in confinement effects.

1. Röllen et al. 2018, PLOS ONE 13(7): e0200746.
2. Stadler et al. 2016, Biophysical Journal 110(5), 1064–1074
3. Stadler et al. 2014, Journal of the American Chemical Society 136 (19), 6987-6994
4. Ameseder et al. 2018, Physical Chemistry Chemical Physics 20 (7), 5128-5139
5. Ameseder et al. 2018, The Journal of Physical Chemistry Letters 9, 2469-2473

Nicolas Coquelle
College 8 Secretary