Iron biomineral core structure of in vitro reconstituted human ferritins overexpressed in E-coli: A M\"{o}ssbauer investigation.

POSTER

Abstract

Ferritin is a protein responsible for the storage of iron in living organisms. Ferritin is composed of a protein shell and an iron biomineral core consisting of ferrihydrite. M\"{o}ssbauer spectroscopy can be used to find the oxidation state and coordination symmetry of the iron ions and overall electronic and magnetic properties of the core. Using this spectroscopic technique we have tested the core-shell model of ferritin on engineered proteins overexpress in \textit{E. coli}, containing various ratios of heavy (H) and light (L) chains. The core-shell model states that the biomineral core is composed of a magnetically ordered inner core and an outer magnetically disordered shell. Due to its nanometric size (d\textasciitilde 7 nm) the ferritin core is superparamagnetic at room temperature, which means that the magnetic moments of the iron ions are constantly flipping in direction. Our study probes the structure and superparamagnetic properties of the core and their dependence on the nature of the protein shell. Preliminary results seem to validate the core-shell model of the ferritin core and shed some light on its dependence on the H/L chain ratios, $i.e$., the number of ferroxidase centers on the protein.

Authors

  • Steve Kim

    Department of Physics, Villanova University

  • Shahab Derakhshan

    Drexel University, Univ of Delaware, Princeton University, Naval Surface Warfare Center\Carderock Division\West Bethesda site, Naval Surface Warfare Center and Georgetown Univ., Dept. of Physics and Astronomy, University of Delaware, Dept. of Physics and Astronomy, University of Deleware, Dept. of Physics and Astronomy, University of Nevada-Reno, university of Delaware, Contributors, Department of Physics, Astronomy and Geosciences, Towson University, Choice Research Group, Univ of the Sciences in Philadephia, Rutgers Univ, National Institute of Standards and Technology, Department of Chemistry, West Chester University, West Chester, PA 19383, Bucknell University, Towson University, University of Maryland, College of William and Mary, Naval Research Laboratory, Department of Physics, Villanova University, Department of Chemistry, Faculty of Medicine, University of Brescia, Department of Chemistry, State University of New York at Potsdam, Delaware State University DE, NIH Bethesda MD, Wilmington Friends School DE, University Of Rochester NY, Delaware State University, Department of Physics and Astronomy,West Virginia University, The National Energy Technology Laboratory, Non-tenure track professor at research institution, Government Sponsored Laboratory, Research and Development at Industrial Company, Tenure-track Professor at 4 yr college, Department of Physics and Astronomy and Department of Chemistry and Biochemistry, University of Delaware, Biology and Soft Matter Division, Oak Ridge National Laboratory, and Department of Physics and Astronomy, The University of Tennessee, Biology and Soft Matter Division, Oak Ridge National Laboratory, Lehigh Univ, Johns Hopkins Univ, NIST, GMU, GWU, Lock Haven University of PA, Univ of Maryland-Balt County; Center for Nanoscale Materials, Argonne National Laboratory, Department of Chemistry, Northwestern University, Univ of Maryland-Balt County, Pennsylvania State University, BAE Systems, Inc., Nashua, New Hampshire 03061, Department of Physics, West Virginia University, Morgantown, West Virginia, 26506-6315, California State University, Long Beach

  • Shahab Derakhshan

    Drexel University, Univ of Delaware, Princeton University, Naval Surface Warfare Center\Carderock Division\West Bethesda site, Naval Surface Warfare Center and Georgetown Univ., Dept. of Physics and Astronomy, University of Delaware, Dept. of Physics and Astronomy, University of Deleware, Dept. of Physics and Astronomy, University of Nevada-Reno, university of Delaware, Contributors, Department of Physics, Astronomy and Geosciences, Towson University, Choice Research Group, Univ of the Sciences in Philadephia, Rutgers Univ, National Institute of Standards and Technology, Department of Chemistry, West Chester University, West Chester, PA 19383, Bucknell University, Towson University, University of Maryland, College of William and Mary, Naval Research Laboratory, Department of Physics, Villanova University, Department of Chemistry, Faculty of Medicine, University of Brescia, Department of Chemistry, State University of New York at Potsdam, Delaware State University DE, NIH Bethesda MD, Wilmington Friends School DE, University Of Rochester NY, Delaware State University, Department of Physics and Astronomy,West Virginia University, The National Energy Technology Laboratory, Non-tenure track professor at research institution, Government Sponsored Laboratory, Research and Development at Industrial Company, Tenure-track Professor at 4 yr college, Department of Physics and Astronomy and Department of Chemistry and Biochemistry, University of Delaware, Biology and Soft Matter Division, Oak Ridge National Laboratory, and Department of Physics and Astronomy, The University of Tennessee, Biology and Soft Matter Division, Oak Ridge National Laboratory, Lehigh Univ, Johns Hopkins Univ, NIST, GMU, GWU, Lock Haven University of PA, Univ of Maryland-Balt County; Center for Nanoscale Materials, Argonne National Laboratory, Department of Chemistry, Northwestern University, Univ of Maryland-Balt County, Pennsylvania State University, BAE Systems, Inc., Nashua, New Hampshire 03061, Department of Physics, West Virginia University, Morgantown, West Virginia, 26506-6315, California State University, Long Beach

  • Shahab Derakhshan

    Drexel University, Univ of Delaware, Princeton University, Naval Surface Warfare Center\Carderock Division\West Bethesda site, Naval Surface Warfare Center and Georgetown Univ., Dept. of Physics and Astronomy, University of Delaware, Dept. of Physics and Astronomy, University of Deleware, Dept. of Physics and Astronomy, University of Nevada-Reno, university of Delaware, Contributors, Department of Physics, Astronomy and Geosciences, Towson University, Choice Research Group, Univ of the Sciences in Philadephia, Rutgers Univ, National Institute of Standards and Technology, Department of Chemistry, West Chester University, West Chester, PA 19383, Bucknell University, Towson University, University of Maryland, College of William and Mary, Naval Research Laboratory, Department of Physics, Villanova University, Department of Chemistry, Faculty of Medicine, University of Brescia, Department of Chemistry, State University of New York at Potsdam, Delaware State University DE, NIH Bethesda MD, Wilmington Friends School DE, University Of Rochester NY, Delaware State University, Department of Physics and Astronomy,West Virginia University, The National Energy Technology Laboratory, Non-tenure track professor at research institution, Government Sponsored Laboratory, Research and Development at Industrial Company, Tenure-track Professor at 4 yr college, Department of Physics and Astronomy and Department of Chemistry and Biochemistry, University of Delaware, Biology and Soft Matter Division, Oak Ridge National Laboratory, and Department of Physics and Astronomy, The University of Tennessee, Biology and Soft Matter Division, Oak Ridge National Laboratory, Lehigh Univ, Johns Hopkins Univ, NIST, GMU, GWU, Lock Haven University of PA, Univ of Maryland-Balt County; Center for Nanoscale Materials, Argonne National Laboratory, Department of Chemistry, Northwestern University, Univ of Maryland-Balt County, Pennsylvania State University, BAE Systems, Inc., Nashua, New Hampshire 03061, Department of Physics, West Virginia University, Morgantown, West Virginia, 26506-6315, California State University, Long Beach

  • Shahab Derakhshan

    Drexel University, Univ of Delaware, Princeton University, Naval Surface Warfare Center\Carderock Division\West Bethesda site, Naval Surface Warfare Center and Georgetown Univ., Dept. of Physics and Astronomy, University of Delaware, Dept. of Physics and Astronomy, University of Deleware, Dept. of Physics and Astronomy, University of Nevada-Reno, university of Delaware, Contributors, Department of Physics, Astronomy and Geosciences, Towson University, Choice Research Group, Univ of the Sciences in Philadephia, Rutgers Univ, National Institute of Standards and Technology, Department of Chemistry, West Chester University, West Chester, PA 19383, Bucknell University, Towson University, University of Maryland, College of William and Mary, Naval Research Laboratory, Department of Physics, Villanova University, Department of Chemistry, Faculty of Medicine, University of Brescia, Department of Chemistry, State University of New York at Potsdam, Delaware State University DE, NIH Bethesda MD, Wilmington Friends School DE, University Of Rochester NY, Delaware State University, Department of Physics and Astronomy,West Virginia University, The National Energy Technology Laboratory, Non-tenure track professor at research institution, Government Sponsored Laboratory, Research and Development at Industrial Company, Tenure-track Professor at 4 yr college, Department of Physics and Astronomy and Department of Chemistry and Biochemistry, University of Delaware, Biology and Soft Matter Division, Oak Ridge National Laboratory, and Department of Physics and Astronomy, The University of Tennessee, Biology and Soft Matter Division, Oak Ridge National Laboratory, Lehigh Univ, Johns Hopkins Univ, NIST, GMU, GWU, Lock Haven University of PA, Univ of Maryland-Balt County; Center for Nanoscale Materials, Argonne National Laboratory, Department of Chemistry, Northwestern University, Univ of Maryland-Balt County, Pennsylvania State University, BAE Systems, Inc., Nashua, New Hampshire 03061, Department of Physics, West Virginia University, Morgantown, West Virginia, 26506-6315, California State University, Long Beach