title: A hydrodynamic study with quasielastic light scattering and sedimentation of bacterial elongation factor EF-Tu.guanosine-5'-diphosphate complex under nonassociating conditions.
abstract: The hydrodynamics of the bacterial elongation factor EF-Tu have been studied in the presence of its ligand guanosine-5'-diphosphate (GDP) by sedimentation in the ultracentrifuge and quasielastic light scattering. Sedimentation studies have made it possible to establish experimental conditions under which only negligible aggregation of the protein occurs (neutral pH, concentration less than 3 mg/mL). Analysis of the light intensity autocorrelation functions under these conditions revealed two independent scattering species with diffusion coefficients of 0.71 X 10(-6) and 0.04 X 10(-6) cm2 s-1. The material with the lower diffusion coefficient, i.e., the aggregates, represented less than 1% of the total number of EF-Tu particles. The other 99% diffused as monomeric molecules with a molar mass corresponding to the value calculated from the known primary structure of the protein. The hydrodynamic parameters derived from the experimental data suggest that EF-Tu.GDP in solution is close to a spherical particle.
authors.affiliation: Department of Physical and Macromolecular Chemistry, Gorlaeus Laboratories, Leiden University, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Sam
authors.forename: C
authors.initials: C
authors.lastname: Pley
authors.forename: M
authors.initials: M
authors.lastname: Mandel
mesh_terms: D004926:Escherichia coli / Q000378:metabolism; D006157:Guanosine Monophosphate / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008027:Light; D008433:Mathematics; D010444:Peptide Elongation Factor Tu / Q000737:chemistry*; D012542:Scattering, Radiation; D013816:Thermodynamics; D014461:Ultracentrifugation
chemical_list: D006157:Guanosine Monophosphate; D010444:Peptide Elongation Factor Tu