Iron plays an integral role in many biochemical processes essential for life.
Now, working in part at SSRL's Beam Line 9-2, a team of researchers led by
Martin Lawrence from Montana State University has solved the structure of a
protein critical to the process of importing iron into cells. The results were
published in the May 27, 2008 edition of the Proceedings of the National
Academy of Sciences.
In humans, iron is predominantly found in hemoglobin, the oxygen carrying
component in red blood cells (RBCs). As RBCs mature, they incorporate iron into
hemoglobin. A protein called Steap3 plays a crucial role in this process.
The Steap family includes four proteins involved in various crucial processes.
Malfunction or overexpression of Steap proteins is associated with a range of
diseases, from anemia to prostate cancer. In the current study, the team solved
the structure of the oxidoreductase domain of Steap3 responsible for changing
the oxidation state of iron from Fe3+ to Fe2+. This step
makes it possible for iron to enter the RBC precursor cells where it can be
incorporated into heme, the molecule that gives hemoglobin the capacity for
Understanding the unique structure of the oxidoreductase domain of Steap3 could
lead to more precisely targeted drugs for treating certain disorders, with
fewer side effects. Research is ongoing to understand the overall structures of
the other Steap proteins.
The project was carried out in collaboration with Mark D. Fleming from
Children's Hospital and Harvard Medical School, Boston.
To learn more about this research see the full scientific highlight at:
Anoop K. Sendamarai, Robert S. Ohgami, Mark D. Fleming, and C. Martin Lawrence
(2008). Structure of the membrane proximal oxidoreductase domain of human
Steap3, the dominant ferrireductase of the erythroid transferrin cycle. Proc.
Natl. Acad. Sci., 105:7410-7415.