Conformational Ensembles from Experimental Data and Computer Simulations

Conformational Ensembles from Experimental Data and Computer Simulations

Poster Abstracts

77-POS Board 37 Unfolding Pathway of Human Serum Albumin Studied by Isothermal Chemical Denaturation and Molecular Dynamics Simulations Rikke L. Knudsen, Alina Kulakova, Sowmya Indrakumar, Pernille Harris, Jens T. Bukrinski, Günther H. Peters . Technical University of Denmark, 2800 Kgs. Lyngby, Denmark. Protein aggregation is one of the grand problems of biophysics. It is highly complex, sensitive to initial conditions, operates on a wide range of timescales and its products range from dimeric proteins to macroscopic fibrils. Unwanted aggregation, for instance, has implications in biotechnology, where protein aggregation leads to reduced yield in bioprocessing, and human health, where aggregation-based diseases such as Alzheimer, Parkinson, and Huntington affect millions of people. Hence, an understanding of the molecular mechanisms underlying protein aggregation is of great relevance in diverse research fields such as medicine, pharmacy, food science and industrial biotechnology. The challenge is when proteins are exposed to conditions that are far from physiological conditions and where stability and solubility become critical. The aim of the current study is to gain better fundamental understanding of the relation between protein properties and their role in protein aggregation propensity, and to explore on a molecular level how solution conditions (e.g. pH) affect protein stability. We have chosen human serum albumin as a model system to study the pH-induced unfolding of the protein applying isothermal chemical denaturation (ICD) and classical molecular dynamics simulations. ICD measurements are performed at different pHs and concentrations of the denaturing agents urea and guanidine hydrochloride. The study was supplemented by classical molecular dynamics simulations performed at different pHs to provide a molecular understanding of the unfolding pathway and to identify specific regions in the proteins that act as hotspots driving protein instability and hence protein aggregation.

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