Berlin 2015 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 50: Biotechnology and bioengineering

BP 50.2: Vortrag

Donnerstag, 19. März 2015, 17:45–18:00, H 1058

Interaction between Polyelectrolytes and Proteins in aqueous solution. — •Shun Yu, Xiao Xu, Joachim Dzubiella, and Matthias Ballauff — Helmholtz-Zentrum Berlin, Intitute Soft Matter and Functional Materials

Complex self-assembling systems of interacting polyelectrolyte (PE) and proteins are a growing topic in recent research in pharmacy, biochemistry/-physics and medicine [1]. The adsorption of unwanted short polyelectrolytes upon proteins in blood plasma and thus hindering their function is a crucial medical problem. To improve the removal of low molecular weight toxins, a deeper understanding of the interaction between the toxin and the protein is crucial. We use Polyacrylic acid (PAA) as a model polymer and study its interaction with Human Serum Albumin (HSA) at a pH well above the isoelectric point of HSA. It has been recognised, that complex formation can occur at the "wrong side of pI", where both protein and polyelectrolyte are same charged [2]. Driving forces of the interaction can be very well studied using Isothermal Titration Calorimetry (ITC) to analyse binding strengths, entropy and enthalpy [3]. In the present work, we show a full thermodynamic analysis of the binding behavior and find a strong dependency of the interaction on ionic strenght and temperature. Moreover, theoretical modelling using MD simulations supports experimental results and quantifies the role of electrostatic field in the binding process.

[1] Kayitmazer et al., Soft Matter 9, 2553 (2013)

[2] Dubin et al., Separation & Purification Reviews 23, 1 (1994)

[3] Welsch et al., Polymer 12, 2835 (2013)