Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: Postersession III

BP 15.64: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster B

Mean field coarse-grained modeling of Protein Folding in Complex Lasso structures — •Claudio Perego and Raffaello Potestio — Max Planck Institute for Polymer Research, Mainz (Germany)

Complex Lassos have been recently identified as a significant class of entangled proteins. These motifs are charactierized by a covalent loop determined by a disulphide bridge. As the protein collapses into its native fold the covalent loop is threaded by part of the polypeptide chain, forming a non-trivial topology. The disulphide bridge can establish under oxidizing conditions, while it does not in reducing environment. It is therefore possible to exploit this feature as an on/off switch of the lasso motif, investigating how topological complexity can affect the folding and the biological activity of the protein. We here present a molecular dynamics study of the Complex Lasso protein folding. We employ a coarse-grained description of the polypeptide, that includes only local interactions, plus an attractive potential modeling the disulphide bridges. The simplicity of our model makes it possible to collect a larger statistics of folding with respect to ordinary structure-based models. Building on this advantage we introduce a genetic scheme for the tuning of the force-field in order to optimize the protein folding rate. This procedure allows us to retrieve insights of great interest for the understanding of complex lasso folding, such as the optimal folding pathways. By excluding the disulphide bridge potential we can also compare the behavior of our model in the oxidized and reduced states, assessing the impact of the complex lasso topology.