Regensburg 2025 – scientific programme

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BP: Fachverband Biologische Physik

BP 30: Protein Structure and Dynamics

BP 30.7: Talk

Thursday, March 20, 2025, 17:00–17:15, H46

Probing the dynamics of small unilamellar vesicles inside Synapsin pools using X-ray photon correlation spectroscopy — •Titus Czajka¹, András Major¹, Hendrik Bruns¹, Christian Hoffmann², Dragomir Milovanovic², and Tim Salditt¹ — ¹Georg-August-Universität Göttingen — ²Deutsches Zentrum für Neurodegenerative Erkrankungen, Berlin

The dynamics of many subcellular biological processes are difficult to access directly with microscopic techniques due to the resolution limit. Length and time scales beyond those accessible by conventional light microscopy can be probed via X-ray photon correlation spectroscopy (XPCS), even in dense media, by analysing the intensity autocorrelation function at different scattering vectors. However, the low scattering cross section of dilute biological samples and the sensitivity to radiation damage complicate the application of XPCS to biological systems. We have coated silica nanoparticles with a lipid bilayer to improve the scattering strength and overcome these challenges. Using such colloid-supported lipid bilayers (CSLBs), we have studied the dynamics of small unilamellar vesicles within synapsin protein pools, a system that exhibits evidence of both liquid-like and network-like phases. Our results show distinct diffusion constants at varying protein concentrations and provide evidence for non-diffusive behaviour within the pools.

Keywords: XPCS; Vesicles; Synapsin; colloid supported lipid bilayers