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BP: Fachverband Biologische Physik
BP 17: Protein Structure and Dynamics
BP 17.6: Vortrag
Mittwoch, 29. März 2023, 16:30–16:45, BAR 0106
Efficiency and selectivity in the self-assembly of SAS-6 rings on a surface — •Santiago Gomez Melo1, Dennis Wörthmüller1, Pierre Gönczy2, Niccolo Banterle3, and Ulrich Schwarz1 — 1Heidelberg University, Heidelberg, Germany — 2EPFL, Lausanne, Switzerland — 3EMBL, Heidelberg, Germany
Centrioles are large cylindrical structures that organize various microtubule-based processes in cells, including the formation of cilia and spindles. Their characteristic nine-fold symmetry results from rings that are formed by dimers of the protein SAS-6. Recently it was observed that the self-assembly of SAS-6 rings is strongly facilitated on a surface. Moreover, a fraction of non-canonical symmetries (i.e., different from nine) was observed. To better understand the factors that determine the efficiency and selectivity of this process, we have performed Brownian Dynamics computer simulations with patchy particles, in which we varied interaction energies and angular binding range. For weak interaction energies and large angular range, we find that the assembly kinetics can be described well by the coagulation-fragmentation equations in the reaction-limited approximation. In contrast, large interaction energies and small angular range lead to kinetic trapping and diffusion-limited assembly. Comparison with experimental data suggests that the SAS-6 system combines a weak binding energy with a small angular range in order to avoid kinetic trapping and favor the desired nine-fold symmetry.