Phase behaviour of thermo-responsive polypeptides
| When |
Nov 28, 2023
from 11:00 to 11:55 |
|---|---|
| Where | Salle des thèses |
| Contact Name | Ralf Everaers |
| Attendees |
Tatiana Morozova |
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Inspired by the aggregate formation in nature, the design of new materials with tailor-made properties received huge attention due to the broad range of their applications, including the fabrication of responsive bio-interfaces, controlled drug-delivery, and release systems, etc. The use of intrinsically disordered protein-based polymers with high control over the protein sequence and length allows for finely tuning the corresponding phase behavior of the system. One example of such bio-polymeric materials is elastin-like polypeptides (ELPs) - artificially derived bio-polymers that mimic the hydrophobic repeat unit in the protein elastin. They typically exhibit a lower critical solution temperature (LCST) phase behavior in an aqueous environment characterized by an expanded-to-collapsed conformational change of a polypeptide chain. In this seminar, I will first present the hydrophobic collapse and assembly of a short ELP: Gly-Val-Gly-(Val-Pro-Gly-Val-Gly)3 employing Molecular Dynamics simulations in conjunction with advanced sampling techniques with an atomistic resolution. In particular, I will discuss how the structural and dynamical properties of these ELPs vary as a function of the concentration in the vicinity of the transition, and which residues are essential for contact formation in multi-chain systems. In the second part of my talk, I will show how the conformational properties and free energy landscape of an ELP with the sequence (Val-Pro-Gly-Val-Gly)n changes as a function of the chain length in the temperature range relevant to ELP’s application. Specifically, I will show how the number of intra-peptide hydrogen bonds, their spacing along the chain, and the lifetime define the conformational ensembles visited by ELPs.