title: Controllable Activation of Nanoscale Dynamics in a Disordered Protein Alters Binding Kinetics.
abstract: The phosphorylation of specific residues in a flexible disordered activation loop yields precise control of signal transduction. One paradigm is the phosphorylation of S339/S340 in the intrinsically disordered tail of the multi-domain scaffolding protein NHERF1, which affects the intracellular localization and trafficking of NHERF1 assembled signaling complexes. Using neutron spin echo spectroscopy (NSE), we show salt-concentration-dependent excitation of nanoscale motion at the tip of the C-terminal tail in the phosphomimic S339D/S340D mutant. The "tip of the whip" that is unleashed is near the S339/S340 phosphorylation site and flanks the hydrophobic Ezrin-binding motif. The kinetic association rate constant of the binding of the S339D/S340D mutant to the FERM domain of Ezrin is sensitive to buffer salt concentration, correlating with the excited nanoscale dynamics. The results suggest that electrostatics modulates the activation of nanoscale dynamics of an intrinsically disordered protein, controlling the binding kinetics of signaling partners. NSE can pinpoint the nanoscale dynamics changes in a highly specific manner.
authors.affiliation: Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA. Electronic address: dcallaway@ccny.cuny.edu.
authors.forename: David J E
authors.initials: DJE
authors.lastname: Callaway
authors.affiliation: Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weiss
authors.affiliation: Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Stingaciu
authors.affiliation: Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Stanley
authors.affiliation: Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: William T
authors.initials: WT
authors.lastname: Heller
authors.affiliation: Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA. Electronic address: zbu@ccny.cuny.edu.
authors.forename: Zimei
authors.initials: Z
authors.lastname: Bu
mesh_terms: D002850:Chromatography, Gel; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D053838:Scattering, Small Angle; D017923:Sodium-Hydrogen Exchangers / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013057:Spectrum Analysis
chemical_list: D050505:Mutant Proteins; D010750:Phosphoproteins; D017923:Sodium-Hydrogen Exchangers; C093376:sodium-hydrogen exchanger regulatory factor
keywords: disordered protein; nanoscale protein motion; neutron spin echo spectroscopy; protein binding kinetics; protein dynamics