[8] The DDB1 gene encodes the large subunit of DNA damage-binding protein, a heterodimer composed of a large and a small (DDB2) subunit.

DDB1 contains 1140 amino acids, amounting to a mass of 127 kDa.

Since then, researchers have found that DDB1 primarily functions as a core component of the CUL4A- and CUL4B-based E3 ubiquitin ligase complexes.

[9] These DCAFs are often ubiquitin ligase substrates and regulate numerous essential processes in the cell including DNA repair (DDB2), DNA replication, chromatin remodeling (Cdt2) and more.

DDB1 has been shown to interact with Transcription initiation protein SPT3 homolog,[10] GCN5L2,[11] DDB2,[12][13] CUL4A,[13] CUL4B[13] and P21.