Dresden 2026 – scientific programme
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BP: Fachverband Biologische Physik
BP 18: Focus session: Integrative Structural Modeling
BP 18.3: Talk
Wednesday, March 11, 2026, 11:15–11:30, BAR/0106
Structural dynamics and long-range interactions controlling timing of the Neurospora circadian clock — •Muriel Hartsch1, Ida Marie Vedel1, Kathrin Motzny1, Michael Brunner2, and Sigrid Milles1 — 1Leibniz-FMP Berlin, Robert-Roessle-Str. 10, 13125 Berlin — 2Heidelberg University, Biochemistry Center (BZH), Im Neuenheimer Feld 328, 69120 Heidelberg
The function and maintenance of the circadian clock in Neurospora crassa are governed by a feedback loop involving both negative and positive regulatory elements, which together drive the oscillating circadian rhythm with a period of approximately 24 hours. The dimeric, intrinsically disordered protein FREQUENCY (FRQ) is a key component of the negative feedback complex and subject to post-transcriptional hyperphosphorylation by casein kinase 1a (CK1a). Phosphorylation of clock proteins is highly conserved across species, from fungi to mammals, with the human PERIOD (PER) protein being a notable example. However, the precise functions associated with hyperphosphorylation remain poorly understood. We hypothesize that time-dependent hyperphosphorylation of FRQ at multiple sites facilitates a transition from closed to open conformation, regulating interactions with its partners. Using nuclear magnetic resonance (NMR) and single-molecule fluorescence resonance energy transfer (smFRET), we investigate the conformational dynamics going along with FRQ phosphorylation by recombinant CK1a. This will allow, combined with structural modeling of the intrinsically disordered protein, to understand how phosphorylation alters the conformation and triggers a switch in FRQ.
Keywords: circadian; clock; intrinsically; disordered; modeling