A novel DNA-binding motif shares structural homology to DNA replication and repair nucleases and polymerases.

A novel class of DNA-binding domains has been established from at least sixteen recently identified DNA-binding proteins. The three-dimensional structure of one of these domains, Mrf-2, has been solved using NMR methods. This structure is significantly different from known DNA-binding domain structures. The mechanism of DNA recognition by this motif has been suggested based on conserved residues, surface electrostatic potentials and chemical shift changes. This new DNA-binding motif shares structural homology with T4 RNase H, E. coli endonuclease III and Bacillus subtilis DNA polymerase I. The structural homology suggests a mechanism for substrate recognition by these enzymes.