SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Poster Session II

CPP 35.48: Poster

Wednesday, March 29, 2023, 11:00–13:00, P1

Statistical Analysis of the Dimerization of Polyglutamine Chains — •Christian Lauer and Wolfgang Paul — Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany

We are presenting a numerical investigation of the dimerization of polyglutamine homo-peptides of varying length. We use the intermediate resolution protein model PRIME20 and study it with a flat-histogram type Monte Carlo simulation. This gives us access to the thermodynamic equilibrium of this model over the complete control parameter range, which for our simulations is the temperature. For densities comparable to typical in vitro experimental conditions we find that the aggregation and folding of the polyglutamine chains occur concurrently. However, as a function of chain length the sequence of establishment of intra- and intermolecular hydrogen bonding contacts changes. Chains longer than about N=24 polyglutamine repeat units fold first and then aggregate. This agrees well with the experimental finding, that beyond N=24 the single polyglutamine chain is the critical nucleus for the aggregation of amyloid fibrils. A finite size scaling of the ordering temperatures reveals that for this chain length (and longer chains) folding occurs at physiological (respectively larger) temperatures whereas shorter chains are disordered at physiological conditions.