Dr. N. DENNIS CHASTEEN
PROFESSOR OF CHEMISTRY, EMERITIS
Department of Chemistry
Office: (603) 862-2520
INTERESTS: EPR, ESEEM & ENDOR Spectroscopy; metallobiochemistry, radicals
in proteins, transition metal chemistry, biomineralization, iron proteins and
complexes, vanadium proteins and complexes.
Our research program is devoted to studies of the bioinorganic and
biophysical chemistry of metalloproteins, in particular those proteins involved
in the metabolism of iron, i.e. ferritin and transferrin. In addition we
have an interest in vanadium biochemistry and in proteins that play a role in
shell biomineralization in mollusks. We are also involved in a number of
collaborative projects with other faculty at
The ferritins are a class of iron storage proteins found widely distributed
among the animal, plant and microbial kingdoms. These proteins consist of 24
subunits assembled into hollow spherical structure within which iron is stored
as a hydrous ferric oxide mineral core. Our research focuses on understanding
the redox and hydrolysis-mineralization mechanisms by which iron is acquired
and released by ferritin. We seek to understand the structural attributes by
which this unusual protein is capable of reversibly storing such large
quantities of iron (4500 Fe/protein). A variety of spectroscopic, kinetic and
thermochemical techniques and site-directed mutagenesis are employed in this
research (see Methodologies and Major Instrumentation).
Shell structure of ferritin.*
Ferroxidase site of human ferritin.**
Transferrin - The transferrins are a class of nonheme iron binding proteins
primarily found in mammals. They include serum transferrin, ovotransferrin,
lactoferrin and melanotransferrin. Serum transferrin, the subject of our
research, is a transport protein that carries iron in the circulation to
various iron requiring tissues such as bone marrow where it is released for the
synthesis of heme proteins. Our work is directed at understanding the spectral,
structural and kinetic properties of the protein as they relate to its function
in vivo. We collaborate with researchers at the University Vermont on studies
of various structurally altered half-molecule transferrins (see Collaborations and Recent Publications).
Bilobal structure of transferrin.*
Iron coordination in transferrin.***
*Protein structures derived from the protein data base (PDB).
**Adapted from X. Yang, Y. Chen-Barrett, P. Arosio and N. D. Chasteen (1998), Biochemistry 37, 9743.
***Adapted from E. N. Baker (1994), Adv. Inorg. Chem. 41, 389.
Last updated 8/12/2013