1. Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305, United States
2. Council for BioIron at CHORI (Children's Hospital Oakland Research Institute), 747 52nd Street, Oakland, California 94609, United States
3. Department of Nutritional Sciences and Molecular Toxicology, University of California—Berkeley, Morgan Hall, Berkeley, California 94720-3104, United States