Figure 1.

Domain structures of ATP-dependent ligases. Schematic representation of the domain structures of DNA ligases I, IIIα, IIIβ and IV, together with ATP-dependent ligases from poxviruses (vaccinia, variola, fowlpox, and so on), the Chlorella virus of Paramecium bursaria PBCV-1, and archaea. Abbreviations: CD, catalytic domain; NCD, conserved non-catalytic domain; PBM, PCNA binding motif; NLS, nuclear localization signal; MTS, mitochondrial targeting sequence; ZnF, putative zinc finger; BRCT, BRCA carboxy-terminal-related domain. The red-boxed regions have had their structures solved crystallographically; the blue-boxed regions are found only in proteins targeted to mitochondria.