This domain called GIY-YIG is found in the amino terminal region of excinuclease abc subunit c (uvrC), bacteriophage T4 endonucleases segA, segB, segC, segD and segE; it is also found in putative endonucleases encoded by group I introns of fungi and phage. The structure of I-TevI a GIY-YIG endonuclease, reveals a novel alpha/beta-fold with a central three-stranded antiparallel beta-sheet flanked by three helices [4]. The most conserved and putative catalytic residues are located on a shallow, concave surface and include a metal coordination site.

1: Identification of a family of bacteriophage T4 genes encoding proteins similar to those present in group I introns of fungi and phage. Sharma M, Ellis RL, Hinton DM; Proc Natl Acad Sci U S A 1992;89:6658-6662. PMID:1631169

2: Conserved domains in DNA repair proteins and evolution of repair systems. Aravind L, Walker DR, Koonin EV; Nucleic Acids Res 1999;27:1223-1242. PMID:9973609

3: Configuration of the catalytic GIY-YIG domain of intron endonuclease I-TevI: coincidence of computational and molecular findings. Kowalski JC, Belfort M, Stapleton MA, Holpert M, Dansereau JT, Pietrokovski S, Baxter SM, Derbyshire V; Nucleic Acids Res 1999;27:2115-2125. PMID:10219084

4: Catalytic domain structure and hypothesis for function of GIY-YIG intron endonuclease I-TevI. Van Roey P, Meehan L, Kowalski JC, Belfort M, Derbyshire V; Nat Struct Biol 2002;9:806-811. PMID:12379841

5: Phylogenomic analysis of the GIY-YIG nuclease superfamily. Dunin-Horkawicz S, Feder M, Bujnicki JM; BMC Genomics. 2006;7:98. PMID:16646971