title: Protein diffusion in crowded electrolyte solutions.
abstract: We report on a combined cold neutron backscattering and spin-echo study of the short-range and long-range nanosecond diffusion of the model globular protein bovine serum albumin (BSA) in aqueous solution as a function of protein concentration and NaCl salt concentration. Complementary small angle X-ray scattering data are used to obtain information on the correlations of the proteins in solution. Particular emphasis is put on the effect of crowding, i.e. conditions under which the proteins cannot be considered as objects independent of each other. We thus address the question at which concentration this crowding starts to influence the static and in particular also the dynamical behaviour. We also briefly discuss qualitatively which charge effects, i.e. effects due to the interplay of charged molecules in an electrolyte solution, may be anticipated. Both the issue of crowding as well as that of charge effects are particularly relevant for proteins and their function under physiological conditions, where the protein volume fraction can be up to approximately 40% and salt ions are ubiquitous. The interpretation of the data is put in the context of existing studies on related systems and of existing theoretical models.
authors.affiliation: Institut für Angewandte Physik, Universität Tübingen, D-72076 Tübingen, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Roosen-Runge
authors.forename: Marcus
authors.initials: M
authors.lastname: Hennig
authors.forename: Tilo
authors.initials: T
authors.lastname: Seydel
authors.forename: Fajun
authors.initials: F
authors.lastname: Zhang
authors.forename: Maximilian W A
authors.initials: MW
authors.lastname: Skoda
authors.forename: Stefan
authors.initials: S
authors.lastname: Zorn
authors.forename: Robert M J
authors.initials: RM
authors.lastname: Jacobs
authors.forename: Marco
authors.initials: M
authors.lastname: Maccarini
authors.forename: Peter
authors.initials: P
authors.lastname: Fouquet
authors.forename: Frank
authors.initials: F
authors.lastname: Schreiber
mesh_terms: D000818:Animals; D004058:Diffusion; D008956:Models, Chemical; D033363:Neutron Diffraction; D011506:Proteins / Q000737:chemistry*; D053838:Scattering, Small Angle; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012996:Solutions
chemical_list: D011506:Proteins; D012996:Solutions; D012710:Serum Albumin, Bovine