Biophysical Society Thematic Meeting | Bucharest 2026

Biophysics of Membrane Reactions in Brian

Poster Abstracts

14-POS Board 14 NUCLEOTIDE EXCHANGE THEORY OF SINGLE-MOLECULE TRACKING DATA IN F-ATPASE Sandor Volkan-Kacso ; California Inst. of Technology, Chemistry and Chemical Engineering, Pasadena, CA, USA When predictive theory is applied to treat single-molecule imaging data, new functional features are revealed, in particular a previously undetectable fast state which was detected in F1-ATPase. This finding by our group, reproduced in two different species of the F1-ATPase motor, is suggesting a universal mechanism whereby the physiological function the release of product ADP is accelerated by 5 orders of magnitude when ATP binds to another site on the motor. A recent analysis of controlled rotation data revealed that the concerted mechanism is kinetically encoded by the angle-dependent rate constant of nucleotide binding and release. A mechanism is suggested for the reverse process of reactant binding assisted product release in the full ATP Synthase. Building on these results, we developed theory-guided automation for data analysis using machine learning algorithms. The detection of the change point in stepping trajectories, i.e., the point that indicates the end of a dwell and the beginning of a step is essential for applying the ergodic principle for the analysis of these trajectories. To do so, we report the development of unsupervised machine learning method. It complements the previously used criteria used to identify the change point, by the natural separation of states seen in the angular phase-space. This approach opens the possibility to test the hypothesized concerted rotary mechanism in other rotary motors, including mammalian F-ATPase, and various V-ATPases.

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