Table 1.
Zero-field splittings for some manganese and iron proteins.
Metal ion | Proteina | Protein ligandsb | D-value (cm−1) | E/D | Method | Reference(s) |
---|---|---|---|---|---|---|
Mn2+ | MnLO | unk | +0.10–0.07 | 0.13–0.23 | EPR 94 GHz | This paper |
Mn2+ | SOD-Az | N3O2(+N) | <0.3 | ~0 | EPR/MCD | 5 |
Mn2+ | MndD | N2O | <0.033 | <0.05 | EPR | 6 |
Mn2+ | ConA | N1O3 | 0.022 | 0.185 | EPR 35 GHz | 7 |
Mn2+ | p21Ras-ADP | O1(+5O) | 0.011 | 0.27 | EPR | 8 |
Fe3+ | sbLO | N3O3 | +1–2 | 0.01–0.065 | EPR/MCD | 15, 17 |
Fe3+ | SOD | N3O2 | >1.5 | 0.24 | EPR 35 GHz | 16 |
Abbreviations: LO, lipoxygenase; SOD-Az, superoxide dismutase-azide complex; MndD, a facial triad protein, Mn2+ dependent 3,4-dihydroxyphenylacetate 2,3-dioxygenase; ConA, concanavalin A; Ras, product of ras gene.
Ligands are contributed by both protein side chains, NxOy, and atoms (+N or O) of small molecules that bind the metal center.