title: Dramatic influence of patchy attractions on short-time protein diffusion under crowded conditions.
abstract: In the dense and crowded environment of the cell cytoplasm, an individual protein feels the presence of and interacts with all surrounding proteins. While we expect this to strongly influence the short-time diffusion coefficientDsof proteins on length scales comparable to the nearest-neighbor distance, this quantity is difficult to assess experimentally. We demonstrate that quantitative information aboutDscan be obtained from quasi-elastic neutron scattering experiments using the neutron spin echo technique. We choose two well-characterized and highly stable eye lens proteins, bovine α-crystallin and γB-crystallin, and measure their diffusion at concentrations comparable to those present in the eye lens. While diffusion slows down with increasing concentration for both proteins, we find marked variations that are directly linked to subtle differences in their interaction potentials. A comparison with computer simulations shows that anisotropic and patchy interactions play an essential role in determining the local short-time dynamics. Hence, our study clearly demonstrates the enormous effect that weak attractions can have on the short-time diffusion of proteins at concentrations comparable to those in the cellular cytosol.
authors.affiliation: Division of Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 16, SE-221 00 Lund, Sweden.
authors.forename: Saskia
authors.identifier: 0000-0001-7612-223X
authors.initials: S
authors.lastname: Bucciarelli
authors.affiliation: Division of Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 16, SE-221 00 Lund, Sweden.; Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Jin Suk
authors.initials: JS
authors.lastname: Myung
authors.affiliation: Institut Laue-Langevin (ILL), F-38042 Grenoble Cedex 9, France.
authors.forename: Bela
authors.initials: B
authors.lastname: Farago
authors.affiliation: Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Shibananda
authors.identifier: 0000-0001-7694-0654
authors.initials: S
authors.lastname: Das
authors.affiliation: Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Gerard A
authors.identifier: 0000-0003-2459-8652
authors.initials: GA
authors.lastname: Vliegenthart
authors.affiliation: Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, D-85748 Garching, Germany.
authors.forename: Olaf
authors.identifier: 0000-0001-6746-7965
authors.initials: O
authors.lastname: Holderer
authors.affiliation: Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Roland G
authors.identifier: 0000-0002-7513-0796
authors.initials: RG
authors.lastname: Winkler
authors.affiliation: Division of Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 16, SE-221 00 Lund, Sweden.
authors.forename: Peter
authors.identifier: 0000-0002-2790-8831
authors.initials: P
authors.lastname: Schurtenberger
authors.affiliation: Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: Gerhard
authors.identifier: 0000-0002-8904-0986
authors.initials: G
authors.lastname: Gompper
authors.affiliation: Division of Physical Chemistry, Department of Chemistry, Lund University, Naturvetarvägen 16, SE-221 00 Lund, Sweden.; Department of Chemistry, University of Fribourg, Chemin du Musée 9, CH-1700 Fribourg, Switzerland.
authors.forename: Anna
authors.identifier: 0000-0003-3310-3412
authors.initials: A
authors.lastname: Stradner
mesh_terms: D000818:Animals; D002417:Cattle; D003198:Computer Simulation; D003459:Crystallins / Q000737:chemistry*; D003593:Cytoplasm / Q000737:chemistry*; D004058:Diffusion
chemical_list: D003459:Crystallins
keywords: Protein crowding; anisotropic interactions; computer simulations; hydrodynamic interactions; multiparticle collision dynamics; neutron spin echo technique; protein diffusion; protein-protein interactions; short-time dynamics