The crystal structure of Dps, a ferritin homolog that binds and protects DNA

The crystal structure of Dps, a DNA-binding protein from starved E. coli that protects DMA from oxidative damage, has been solved at 1.6 Å resolution. The Dps monomer has essentially the same fold as ferritin, which forms a 24-mer with 432 symmetry, a hollow core and pores at the three-fold axes. Dps forms a dodecamer with 23 (tetrahedral) point group symmetry which also has a hollow core and pores at the three-folds. The structure suggests a novel DNA-binding motif and a mechanism for DNA protection based on the sequestration of Fe ions.