FEN-like PIN domains of Flap endonuclease-1 (FEN1)-like and exonuclease-1 (EXO1)-like nucleases, structure-specific, divalent-metal-ion dependent, 5' nucleases; PIN (PilT N terminus) domain of Flap endonuclease-1 (FEN1) and exonuclease-1 (EXO1)-like nucleases: FEN1, EXO1, Mkt1, Gap endonuclease 1 (GEN1) and Xeroderma pigmentosum complementation group G (XPG) nuclease. These nucleases are members of the structure-specific, 5' nuclease family (FEN-like) that catalyzes hydrolysis of DNA duplex-containing nucleic acid structures during DNA replication, repair, and recombination. Canonical members of the FEN-like family possess a PIN domain with a two-helical structure insert (also known as the helical arch, helical clamp or I domain) of variable length (approximately 16 to 800 residues), and at the C-terminus of the PIN domain a H3TH (helix-3-turn-helix) domain, an atypical helix-hairpin-helix-2-like region. Both the H3TH domain (not included in this model) and the helical arch/clamp region are involved in DNA binding. The PIN domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its putative active center, consisting of invariant acidic amino acid residues (putative metal-binding residues), is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 75905763 169 CIRVLRALGYAYINSGrMEADDACANLYHTNTVAYVHTTDTDLLLMGCDIVL 220
Cdd:cd00128  92 CKHLLSLFGIPYVVAP-YEAEAQCAYLLKAGIVDAAITEDSDCLLFGAPRVI 142

FEN-like PIN domains of Flap endonuclease-1 (FEN1)-like and exonuclease-1 (EXO1)-like nucleases, structure-specific, divalent-metal-ion dependent, 5' nucleases; PIN (PilT N terminus) domain of Flap endonuclease-1 (FEN1) and exonuclease-1 (EXO1)-like nucleases: FEN1, EXO1, Mkt1, Gap endonuclease 1 (GEN1) and Xeroderma pigmentosum complementation group G (XPG) nuclease. These nucleases are members of the structure-specific, 5' nuclease family (FEN-like) that catalyzes hydrolysis of DNA duplex-containing nucleic acid structures during DNA replication, repair, and recombination. Canonical members of the FEN-like family possess a PIN domain with a two-helical structure insert (also known as the helical arch, helical clamp or I domain) of variable length (approximately 16 to 800 residues), and at the C-terminus of the PIN domain a H3TH (helix-3-turn-helix) domain, an atypical helix-hairpin-helix-2-like region. Both the H3TH domain (not included in this model) and the helical arch/clamp region are involved in DNA binding. The PIN domain belongs to a large nuclease superfamily. The structural properties of the PIN domain indicate its putative active center, consisting of invariant acidic amino acid residues (putative metal-binding residues), is geometrically similar in the active center of structure-specific 5' nucleases, PIN-domain ribonucleases of eukaryotic rRNA editing proteins, and bacterial toxins of toxin-antitoxin (TA) operons.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 75905763 169 CIRVLRALGYAYINSGrMEADDACANLYHTNTVAYVHTTDTDLLLMGCDIVL 220
Cdd:cd00128  92 CKHLLSLFGIPYVVAP-YEAEAQCAYLLKAGIVDAAITEDSDCLLFGAPRVI 142