InterPro domain: IPR009060

UBA domains are a commonly occurring sequence motif of approximately 45 amino acid residues that are found in diverse proteins involved in the ubiquitin/proteasome pathway, DNA excision-repair, and cell signalling via protein kinases [ 1 ]. HHR23A, the human homologue of yeast Rad23A is a nucleotide excision-repair protein that contains both an internal and a C-terminal UBA domain. The fold of the UBA domain consists of a compact three-helical bundle with a right-handed twist, and have a conserved hydrophobic surface patch for protein-protein interactions. UBA-like domains can be found in other proteins as well, such as the TS-N domain in the elongation factor Ts (EF-Ts), which catalyses the recycling of the GTPase EF-Tu required for the binding of aminoacyl-tRNA top the ribosomal A site [ 2 ]; and the C-terminal domain of TAP/NXF1, which functions in nuclear export through the interaction of its UBA-like domain with FG nucleoporins [ 3 ].

1. Solution structures of UBA domains reveal a conserved hydrophobic surface for protein-protein interactions. J. Mol. Biol. 319, 1243-55
2. Mechanism of elongation factor (EF)-Ts-catalyzed nucleotide exchange in EF-Tu. Contribution of contacts at the guanine base. J. Biol. Chem. 277, 6032-6
3. Structural basis for the interaction between the Tap/NXF1 UBA domain and FG nucleoporins at 1A resolution. J. Mol. Biol. 326, 849-58