Based on the experimental data and homologous sites in Protein Data Bank (P
DB) a model for metal binding sites in D1/D2 heterodimer has been proposed.
On searching for tetranuclear and binuclear Mn binding sites in the PDB, a
suitable sequence homology in thermolysin and D1 could be observed. From t
he homology and site-directed mutagenesis data, a model for binuclear Mn-Ca
or Mn-Mn has been built and it is extended to a tetranuclear Mn centre.