2Fakultät für Physik, E17, Technische Universität München, 85747 Garching, Germany
Tóm tắt
The great similarity between the binding of Fe(II) and the high‐affinity Mn‐binding site in the Mn‐depleted PSII membranes (Semin et al. (1996) FEBS Lett. 375, 223–226) suggests that the coordination sphere of Mn in PSII is also suitable for iron. A comparison is performed between the primary amino acid sequences of D1 and D2 and diiron‐oxo enzymes with the function of oxygen activation. All conservative motifs (EXXH) and residues binding and stabilizing the diiron cluster in diiron‐oxo enzymes have been found in the C‐terminal domains of D1 and D2 polypeptides. On the basis of these sequence similarities we suggest a structural model for the manganese cluster in the oxygen‐evolving complex.
