Crystal structure of T. thermophilus RecJ (PDB ID: 2ZXR). Full-length T. thermophilus RecJ is comprised of domains I–IV and forms a ring-like structure. The catalytic active site is located in the cavity between domains I and II as indicated by an arrow. Domain III shows a structural similarity to the oligonucleotide/oligosaccharide-binding fold that is often found in single-stranded DNA-binding proteins. The ring-like structure and oligonucleotide/oligosaccharide-binding fold will ensure the high processivity and strict specificity for single-stranded DNA.
