title: Hierarchical molecular dynamics of bovine serum albumin in concentrated aqueous solution below and above thermal denaturation.
abstract: The dynamics of proteins in solution is a complex and hierarchical process, affected by the aqueous environment as well as temperature. We present a comprehensive study on nanosecond time and nanometer length scales below, at, and above the denaturation temperature Td. Our experimental data evidence dynamical processes in protein solutions on three distinct time scales. We suggest a consistent physical picture of hierarchical protein dynamics: (i) self-diffusion of the entire protein molecule is confirmed to agree with colloid theory for all temperatures where the protein is in its native conformational state. At higher temperatures T > Td, the self-diffusion is strongly obstructed by cross-linking or entanglement. (ii) The amplitude of backbone fluctuations grows with increasing T, and a transition in its dynamics is observed above Td. (iii) The number of mobile side-chains increases sharply at Td while their average dynamics exhibits only little variations. The combination of quasi-elastic neutron scattering and the presented analytical framework provides a detailed microscopic picture of the protein molecular dynamics in solution, thereby reflecting the changes of macroscopic properties such as cluster formation and gelation.
authors.affiliation: Institut Max von Laue - Paul Langevin (ILL), CS 20156, F-38042 Grenoble, France. seydel@ill.eu.
authors.forename: Marco
authors.initials: M
authors.lastname: Grimaldo
authors.forename: Felix
authors.initials: F
authors.lastname: Roosen-Runge
authors.forename: Marcus
authors.initials: M
authors.lastname: Hennig
authors.forename: Fabio
authors.initials: F
authors.lastname: Zanini
authors.forename: Fajun
authors.initials: F
authors.lastname: Zhang
authors.forename: Niina
authors.initials: N
authors.lastname: Jalarvo
authors.forename: Michaela
authors.initials: M
authors.lastname: Zamponi
authors.forename: Frank
authors.initials: F
authors.lastname: Schreiber
authors.forename: Tilo
authors.initials: T
authors.lastname: Seydel
mesh_terms: D000818:Animals; D002417:Cattle; D006358:Hot Temperature; D056004:Molecular Dynamics Simulation; D011489:Protein Denaturation; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D012710:Serum Albumin, Bovine