title: In Vivo Protein Dynamics on the Nanometer Length Scale and Nanosecond Time Scale.
abstract: Selectively labeled GroEL protein was produced in living deuterated bacterial cells to enhance its neutron scattering signal above that of the intracellular milieu. Quasi-elastic neutron scattering shows that the in-cell diffusion coefficient of GroEL was (4.7 ± 0.3) × 10-12m2/s, a factor of 4 slower than its diffusion coefficient in buffer solution. Internal protein dynamics showed a relaxation time of (65 ± 6) ps, a factor of 2 slower compared to the protein in solution. Comparison to the literature suggests that the effective diffusivity of proteins depends on the length and time scale being probed. Retardation of in-cell diffusion compared to the buffer becomes more significant with the increasing probe length scale, suggesting that intracellular diffusion of biomolecules is nonuniform over the cellular volume. The approach outlined here enables investigation of protein dynamics within living cells to open up new lines of research using "in-cell neutron scattering" to study the dynamics of complex biomolecular systems.
authors.forename: Divina B
authors.initials: DB
authors.lastname: Anunciado
authors.forename: Vyncent P
authors.initials: VP
authors.lastname: Nyugen
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Hurst
authors.forename: Mitchel J
authors.initials: MJ
authors.lastname: Doktycz
authors.forename: Volker
authors.initials: V
authors.lastname: Urban
authors.forename: Paul
authors.initials: P
authors.lastname: Langan
authors.forename: Eugene
authors.identifier: http://orcid.org/0000-0002-5684-2675
authors.initials: E
authors.lastname: Mamontov
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Hugh
authors.identifier: http://orcid.org/0000-0003-2966-5527
authors.initials: H
authors.lastname: O'Neill