Uracil-DNA glycosylase inhibitors, are DNA mimic proteins that prevent the DNA binding sites of UDGs (Uracil DNA glycosylase) from interacting with their DNA substrate. SSP0047 Swiss:Q4A134 (or SAUGI; for Staphylococcus aureus uracil-DNA glycosylase inhibitor) acts as a uracil-DNA glycosylase inhibitor that breaks the uracil-removing activity of S. aureus uracil-DNA glycosylase (SAUDG) Pfam:PF03167 [1]. The SAUGI/SAUDG complex has been determined, and shows that SAUGI binds to the SAUDG DNA binding region via several strong interactions, by using a hydrophobic pocket to hold SAUDG's protruding residue (i.e. SAUDG Leu184, E. coli UDG Leu191 and B. subtilis UDG Phe191). By binding to SAUDG in this way, SAUGI thus prevents SAUDG from binding to its DNA substrate and performing DNA repair activity [2].

1: Staphylococcus aureus protein SAUGI acts as a uracil-DNA glycosylase inhibitor. Wang HC, Hsu KC, Yang JM, Wu ML, Ko TP, Lin SR, Wang AH; Nucleic Acids Res. 2014;42:1354-1364. PMID:24150946

2: Using structural-based protein engineering to modulate the differential inhibition effects of SAUGI on human and HSV uracil DNA glycosylase. Wang HC, Ho CH, Chou CC, Ko TP, Huang MF, Hsu KC, Wang AH; Nucleic Acids Res. 2016;44:4440-4449. PMID:26980279