1. Division of Biomedical Sciences, School of Medicine, University of California Riverside, 900 University Avenue, Riverside, California 92521, United States
2. Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy