Biophysical Society Thematic Meeting | Trieste 2024

Emerging Theoretical Approaches to Complement Single-Particle Cryo-EM

Poster Abstracts

30-POS Board 30 RELATION BETWEEN STRUCTURE AND RATE CONSTANTS IN SINGLE MOLECULE ROTATION OF F1-ATPASE Sandor Volkan-Kacso ; 1 California Inst. of Technology, Chemistry and Chemical Engineering, Pasadena, CA, USA 2 Azusa Pacific University, Mathematics, Physics and Statistics, Azusa, CA, USA In this work we describe a method for extracting, from F1-ATPase controlled rotation experiments, the angle-dependent rate constants for nucleotide binding and release without assuming a particular functional form. Then an analysis of angle-dependent conformational changes using recent Cryo-EM structures is provided. To establish the relation between the rate constants and structure, we employ an angle-dependent theory of nucleotide binding. Using the theory it is shown how the concerted and angel-dependent binding of ATP and release of ADP post-hydrolysis occur in concert both in uni-site occupancy and multi-site conditions. The theory, applied to single-molecule rotation data, also reveals a short-lived state after ATP binding and before the ADP release in a different site. It is concluded that the concerted kinetics is due to a strong structural correlation in the binding cleft opening un one subunit with the closing of the cleft in another subunit in the α 3 β 3 ring.

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