382206 Sequence/Temperature Dependence of Properties of Unfolded/Disordered Proteins

Thursday, November 20, 2014: 1:45 PM
Crystal Ballroom B/E (Hilton Atlanta)
Gul H. Zerze1, Robert Best2 and Jeetain Mittal1, (1)Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, (2)Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD

The unfolded/denatured state of peptides and proteins has attracted prominent interest for decades, for better understanding of protein folding problem, aggregation/misfolding and collapse transitions. Moreover intrinsically disordered proteins (IDPs), which have lack of well-defined tertiary structures yet still have biologically relevant function in the cell, enlarges the interest. In this work, we simulated five different unfolded/disordered peptide chains in aqueous solution for the systematic investigation of their characteristic polymer properties. We used all-atom protein model and explicit solvent which naturally captures temperature-dependent solvation effects. We found that the qualitative scaling behavior of the chains matches expectations from theory under ambient conditions. We also were able to regenerate temperature-induced collapse of polypeptide chains. Change of hydration of individual residues as a function of temperature provides an explanation on the origin of collapse. As a result of the chain collapse, some of the proteins switch from an excluded-volume towards a Flory-type random walk scaling as temperature is increased. Furthermore, we find that unfolded ensembles of peptides at different temperatures are remarkably similar.

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See more of this Session: Thermodynamics of Biomolecular Folding and Assembly
See more of this Group/Topical: Engineering Sciences and Fundamentals