This family contains the N-terminal cupin domain of pirin and pirin-like proteins, including Escherichia coli YhhW and YhaK. Pirin functions as both a transcriptional cofactor and an apoptosis-related protein in mammals and is involved in seed germination and seedling development in plants. Proteins in this family have two tandem cupin-like folds but the C-terminal cupin fold has diverged considerably and does not have a metal binding site. The exact functions of pirins are unknown but they have quercitinase activity in Escherichia coli and are thought to play important roles in transcription and apoptosis. Proteins in this family belong to the cupin superfamily with a conserved "jelly roll-like" beta-barrel fold.
Feature 1: metal binding site [ion binding site], 4 residue positions
Conserved feature residue pattern:H H H E
Evidence:
Comment:The four-coordinate metallocenter usually includes three histidines and one glutamate; however, this protein may bind metal via different amino acids
Structure:1J1L: Homo sapiens pirin binds iron; contacts at 4.0A
Jiyao W et al.(2023). "The conserved domain database in 2023.",