Redox-Promoting Protein Motions in Rubredoxin

Journal Article · Sun May 01 04:00:00 EDT 2011 · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

DOI:https://doi.org/10.1021/jp201346x· OSTI ID:1024288

Borreguero Calvo, Jose M. ^[1]; He, Junhong ^[1]; Meilleur, Flora ^[1]; Weiss, Kevin L. ^[1]; Myles, Dean A A ^[1]; Herwig, Kenneth W. ^[1]; Agarwal, Pratul K. ^[1]

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1. ORNL

Proteins are dynamic objects, constantly undergoing conformational fluctuations, yet the linkage between internal protein motion and function is widely debated. This study reports on the characterization of temperature-activated collective and individual atomic motions of oxidized rubredoxin, a small 53 residue protein from thermophilic Pyrococcus furiosus (RdPf). Computational modeling allows detailed investigations of protein motions as a function of temperature, and neutron scattering experiments are used to compare to computational results. Just above the dynamical transition temperature which marks the onset of significant anharmonic motions of the protein, the computational simulations show both a significant reorientation of the average electrostatic force experienced by the coordinated Fe{sup 3+} ion and a dramatic rise in its strength. At higher temperatures, additional anharmonic modes become activated and dominate the electrostatic fluctuations experienced by the ion. At 360 K, close to the optimal growth temperature of P. furiosus, simulations show that three anharmonic modes including motions of two conserved residues located at the protein active site (Ile7 and Ile40) give rise to the majority of the electrostatic fluctuations experienced by the Fe{sup 3+} ion. The motions of these residues undergo displacements which may facilitate solvent access to the ion.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: DOE Office of Science; USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1024288
• Journal Information: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry Journal Issue: 28 Vol. 115; ISSN 1520-6106
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
ELECTROSTATICS
FLUCTUATIONS
IRON IONS
NEUTRON DIFFRACTION
PROTEINS
RESIDUES
RUBREDOXIN
SCATTERING
SIMULATION
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE