Dresden 2026 – scientific programme
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BP: Fachverband Biologische Physik
BP 14: Poster Session II
BP 14.79: Poster
Tuesday, March 10, 2026, 18:00–21:00, P2
Single-molecule PIE-FRET and nsFCS Studies of Metal Ion-dependent Folding of an rRNA Tertiary Contact — •Mara Henschel1, Vanessa Schumann1, Andreas Hartmann2, Michael Schlierf2, and Richard Börner1 — 1Laserinstitut Hochschule Mittweida, Mittweida, Germany — 2Technische Universität Dresden, Dresden, Germany
Tertiary interactions in ribosomal RNA are crucial for shaping the folding landscape. However, the dynamics of these interactions across different timescales are not well understood. We investigate the tertiary contact of a double fluorescent-labelled ribosomal RNA from Saccharomyces cerevisiae at the single-molecule level in vitro. We quantify metal-ion-dependent folding and dynamics during K(I) and Mg(II) titrations using single-molecule PIE-FRET as a nanometre-distance readout combined with nanosecond fluorescence correlation spectroscopy (nsFCS). FRET-histograms reveals ion-dependent broadening beyond shot noise, indicating structural dynamics on the microsecond to millisecond timescale. Furthermore, nsFCS measurements show fast domain motions ranging from nanoseconds to microseconds. By employing two complementary labeling schemes, we distinguish local folding of the kissing loop from formation of the long-range tertiary contact, resolving distinct folding trajectories within the same RNA construct. Our results provide a dynamic insight of rRNA tertiary-contact formation and lay the foundation for a quantitative, mechanistic model of metal-ion-regulated folding of ribosomal RNA.
Keywords: single-molecule; rRNA; PIE-FRET; nsFCS; metal ion