Two protein domains (left, orange-yellow, and right, green-blue) dimerize to form<unk> . Both domains contain Rossmann-like folds, beta sheets (arrows) surrounded by alpha helices (spirals), which bind UDP-glucuronic acid. No structure of a full human UGT enzyme has been determined yet, however Miley et al. resolved a partial<unk>  structure of the C-terminal portion showing two dimeric domains with Rossman-like folds in complex. The Rossman fold typically binds nucleotide substrates, in this case the UDP-glucuronic acid cofactor involved in glucuronidation by<unk> . Generally, the C-terminus of UGT enzymes is highly conserved and binds the UDP-glucuronic acid cofactor, while the N-terminus (not resolved in this structure) is responsible for substrate binding. This first resolved structure indicated that the C-terminus of one of the two dimers projected into the UDP-glucuronic acid binding site of the second dimer, thus rendering the second dimer ineffective. Further studies have investigated dimerization of UGT enzyme polymorphisms and found both homodimer and heterodimer (with genetic polymorphisms of<unk>  or other UGT enzymes such as UGT1A1) formation are possible, with some combinations having an effect on enzyme activity.
UGT2B7
UGT1A8
UGT1A4
UGT2B4
UGT1A9
CYP2C19
CYP2C8
CYP2D6