Dataset Information

Global Dynamics and Exchange Kinetics of a Protein on the Surface of Nanoparticles Revealed by Relaxation-Based Solution NMR Spectroscopy.

ABSTRACT: The global motions and exchange kinetics of a model protein, ubiquitin, bound to the surface of negatively charged lipid-based nanoparticles (liposomes) are derived from combined analysis of exchange lifetime broadening arising from binding to nanoparticles of differing size. The relative contributions of residence time and rotational tumbling to the total effective correlation time of the bound protein are modulated by nanoparticle size, thereby permitting the various motional and exchange parameters to be determined. The residence time of ubiquitin bound to the surface of both large and small unilamellar liposomes is ?20 ?s. Bound ubiquitin undergoes internal rotation about an axis approximately perpendicular to the lipid surface on a low microsecond time scale (?2 ?s), while simultaneously wobbling in a cone of semiangle 30-55° centered about the internal rotation axis on the nanosecond time scale. The binding interface of ubiquitin with liposomes is mapped by intermolecular paramagnetic relaxation enhancement using Gd(3+)-tagged vesicles, to a predominantly positively charged surface orthogonal to the internal rotation axis.

SUBMITTER: Ceccon A

PROVIDER: S-EPMC5590658 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Global Dynamics and Exchange Kinetics of a Protein on the Surface of Nanoparticles Revealed by Relaxation-Based Solution NMR Spectroscopy.

Ceccon Alberto A Tugarinov Vitali V Bax Ad A Clore G Marius GM

Journal of the American Chemical Society 20160427 18

The global motions and exchange kinetics of a model protein, ubiquitin, bound to the surface of negatively charged lipid-based nanoparticles (liposomes) are derived from combined analysis of exchange lifetime broadening arising from binding to nanoparticles of differing size. The relative contributions of residence time and rotational tumbling to the total effective correlation time of the bound protein are modulated by nanoparticle size, thereby permitting the various motional and exchange para ...[more]

PMID: 27111298

Similar Datasets

Project description:'In dopaminergic neurons, alpha-synuclein (alphaS) partitions between a disordered cytosolic state and a lipid-bound state. Binding of alphaS to membrane phospholipids is implicated in its functional role in synaptic regulation, but also impacts fibril formation associated with Parkinson's disease. We describe here a solution NMR study in which alphaS is added to small unilamellar vesicles of a composition mimicking synaptic vesicles; the results provide evidence for multiple distinct phospholipid-binding modes of alphaS. Exchange between the free state and the lipid-bound alphaS state, and between different bound states is slow on the NMR timescale, being in the range of 1-10 s(-1). Partitioning of the binding modes is dependent on lipid/alphaS stoichiometry, and tight binding with slow-exchange kinetics is observed at stoichiometries as low as 2:1. In all lipid-bound states, a segment of residues starting at the N-terminus of alphaS adopts an alpha-helical conformation, while succeeding residues retain the characteristics of a random coil. The 40 C-terminal residues remain dynamically disordered, even at high-lipid concentrations, but can also bind to lipids to an extent that appears to be determined by the fraction of cis X-Pro peptide bonds in this region. While lipid-bound alphaS exhibits dynamic properties that preclude its direct observation by NMR, its exchange with the NMR-visible free form allows for its indirect characterization. Rapid amide-amide nuclear Overhauser enhancement buildup points to a large alpha-helical conformation, and a distinct increase in fluorescence anisotropy attributed to Tyr39 indicates an ordered environment for this "dark state." Titration of alphaS with increasing amounts of lipids suggests that the binding mode under high-lipid conditions remains qualitatively similar to that in the low-lipid case. The NMR data appear incompatible with the commonly assumed model where alphaS lies in an alpha-helical conformation on the membrane surface and instead suggest that considerable remodeling of the vesicles is induced by alphaS.

Dataset Information

Global Dynamics and Exchange Kinetics of a Protein on the Surface of Nanoparticles Revealed by Relaxation-Based Solution NMR Spectroscopy.

Publications

Global Dynamics and Exchange Kinetics of a Protein on the Surface of Nanoparticles Revealed by Relaxation-Based Solution NMR Spectroscopy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets