Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 23: Biomaterials and biopolymers I (joint session BP/CPP)

BP 23.10: Vortrag

Donnerstag, 4. April 2019, 12:00–12:15, H10

Sequence effects on size, shape, and structural heterogeneity in Intrinsically Disordered Proteins — •Upayan Baul¹, Debayan Chakraborty², Mauro L. Mugnai², John E. Straub³, Devarajan Thirumalai², and Joachim Dzubiella¹ — ¹Institute of Physics, Albert-Ludwigs-University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany — ²Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712 — ³Department of Chemistry, Boston University, Boston, Massachusetts 02215

Intrinsically disordered proteins (IDPs) lack well-defined three-dimensional structures, thus challenging the archetypal notion of structure-function relationships in proteins. We present the development of a coarse grained simulation model that quantitatively characterizes the structural features of IDPs as a function of sequence and length (N_T). For diverse IDP sequences, with N_T ranging from 24 to 441, our simulations not only reproduce the radii of gyration (R_g) obtained from experiments, but also predict the scattering intensity profiles in near quantitative agreement with Small Angle X-ray Scattering experiments. While R_g values are well-described by the standard Flory scaling law, R_g = R₀ N_T^ν, with ν=0.588, analyses reveal that the extent of conformational heterogeneity for IDPs is highly sequence-dependent, even though ensemble-averaged properties suggest synthetic polymer-like behavior in a good solvent. In conclusion, we comment on the effects of external stimuli such as salt concentration and temperature on the conformational properties of polypeptide sequences.