Abstract
AbstractWe experimentally and computationally study the dynamics of homogeneously electrically charged intrinsically disordered proteins (IDPs) in ionic solutions (aqueous solutions containing salt). Computationally, this is achieved by extending a recently introduced discrete elastic rod (DER) model to include electrostatic interactions. The respective model includes only three free parameters: bending stiffness, bond length, and hydrodynamic radius. These parameters were obtained by fitting the measured conformational dynamics of uncharged polypeptides as reported in a previous publication [8]. We compare our computational results with photo-electron transfer fluorescence correlation spectroscopy (PET-FCS) measurements of the conformational dynamics of the highly charged (-44 e−) intrinsically disordered protein Prothymosin α. We here report on an agreement between the loop-closing rates obtained from our computational model and the respective experimental measurements, with rate values significantly slower than those observed for uncharged IDPs.
Publisher
Cold Spring Harbor Laboratory