Side chain electrostatic interactions and pH-dependent expansion of the intrinsically disordered, highly acidic carboxyl-terminus of γ-tubulin.

ABSTRACT: Intramolecular electrostatic attraction and repulsion strongly influence the conformational sampling of intrinsically disordered proteins and domains (IDPs). In order to better understand this complex relationship, we have used nuclear magnetic resonance to measure side chain pK_a values and pH-dependent translational diffusion coefficients for the unstructured and highly acidic carboxyl-terminus of γ-tubulin (γ-CT), providing insight into how the net charge of an IDP relates to overall expansion or collapse of the conformational ensemble. Many of the pK_a values in the γ-CT are shifted upward by 0.3-0.4 units and exhibit negatively cooperative ionization pH profiles, likely due to the large net negative charge that accumulates on the molecule as the pH is raised. pK

SUBMITTER: Payliss BJ 

PROVIDER: S-EPMC6511730 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature