DNA Ligase 1
Space-filling model of DNA Ligase 1 (PDB ID 1x9n). Regions of secondary structures are shown - alpha helices as red and beta-pleated sheets as green. DNA is shown as a spiral, stick-like structure (purple) in the center of the enzyme.
DNA ligases are a class of enzymes that repair (ligate) breaks in the sugar-phosphate backbone of DNA strands. DNA Ligase 1 is a 120kda ATP-dependent ligase that functions in eukaryotic DNA replication and the base excision repair process.