Regensburg 2025 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 30: Protein Structure and Dynamics

BP 30.6: Vortrag

Donnerstag, 20. März 2025, 16:45–17:00, H46

Single molecule FRET studies on folding properties of multidomain protein fragments — •Alida Meyer¹, Alexandros Katranidis², Nuno Bustorff², and Jörg Fitter^1,2 — ¹RWTH Aachen University, I. Physikalisches Institut (IA), AG Biophysik, Aachen, Germany — ²Forschungszentrum Jülich, ER-C-3 Structural Biology, Jülich, Germany

Protein folding and unfolding are crucial for cellular function and stability. This study emloys single-molecule Förster resonance energy transfer (smFRET) to investigate structural transitions in yeast phosphoglycerate kinase (yPGK). We focus on its two-domain structure and the relationship between the Rossmann-fold topology and folding intermediates. Earlier studies with full-length yPGK labelled with fluorescent dyes at multiple different positions allowed to map several different intra-molecular distances during unfolding transitions [1,2]. To mimic co-translational folding properties, we performed smFRET measurements with truncated yPGK fragments. The results are compared with those of full-length proteins, including whether the same type of unfolding transition occurs as in the full-length protein (e.g., two state transitions or compact intermediates). In addition, the results from truncated fragments are also compared with nascent-chain folding in ribosome-nascent chain complexes (RNCs), analyzed via cryo-electron microscopy. These methods provide insights into how domain topology and neighboring structural elements influence multidomain protein folding. [1] Cerminara et al., Biophysical Journal, 2020, 118, 688 [2] Bustorff et al., Biomolecules, 2023, 13, 1280

Keywords: protein folding; smFRET; multiple distance mapping; multidomain proteins; folding intermediates