N-terminal domain of Fpg (formamidopyrimidine-DNA glycosylase, MutM)_Nei (endonuclease VIII) base-excision repair DNA glycosylases; DNA glycosylases maintain genome integrity by recognizing base lesions created by ionizing radiation, alkylating or oxidizing agents, and endogenous reactive oxygen species. These enzymes initiate the base-excision repair process, which is completed with the help of enzymes such as phosphodiesterases, AP endonucleases, DNA polymerases and DNA ligases. DNA glycolsylases cleave the N-glycosyl bond between the sugar and the damaged base, creating an AP (apurinic/apyrimidinic) site. The FpgNei DNA glycosylases represent one of the two structural superfamilies of DNA glycosylases that recognize oxidized bases (the other is the HTH-GPD superfamily exemplified by Escherichia coli Nth). Most FpgNei DNA glycosylases use their N-terminal proline residue as the key catalytic nucleophile, and the reaction proceeds via a Schiff base intermediate. One exception is mouse Nei-like glycosylase 3 (Neil3) which forms a Schiff base intermediate via its N-terminal valine. In addition to this FpgNei_N domain, FpgNei proteins have a helix-two-turn-helix (H2TH) domain and a zinc (or zincless)-finger motif which also contribute residues to the active site. FpgNei DNA glycosylases have a broad substrate specificity. They are bifunctional, in addition to the glycosylase (recognition) activity, they have a lyase (cleaving) activity on the phosphodiester backbone of the DNA at the AP site. This superfamily includes eukaryotic, bacterial, and viral proteins.

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                  ....*....|....*....|....*....|....*..
gi 1207734453   1 MPEGPELHLASQFVNEACRALVFGGCVEKSSVSRNPE 37
Cdd:cd08967     1 MPEGPELHLASLFVNKMCKGLIFTGAVEKSSVSKNPE 37

N-terminal domain of metazoan Nei-like glycosylase 1 (NEIL1); This family contains the N-terminal domain of metazoan NEIL1. It belongs to the FpgNei_N, [N-terminal domain of Fpg (formamidopyrimidine-DNA glycosylase, MutM)_Nei (endonuclease VIII)] domain superfamily. DNA glycosylases maintain genome integrity by recognizing base lesions created by ionizing radiation, alkylating or oxidizing agents, and endogenous reactive oxygen species. They initiate the base-excision repair process, which is completed with the help of enzymes such as phosphodiesterases, AP endonucleases, DNA polymerases and DNA ligases. DNA glycosylases cleave the N-glycosyl bond between the sugar and the damaged base, creating an AP (apurinic/apyrimidinic) site. Most FpgNei DNA glycosylases use their N-terminal proline residue as the key catalytic nucleophile, and the reaction proceeds via a Schiff base intermediate. NEIL1 recognizes the oxidized pyrimidines 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG) and 4,6-diamino- 5-formamidopyrimidine (FapyA), thymine glycol (Tg) and 5-hydroxyuracil (5-OHU). However, even though it has weak activity on 8-oxo-7,8-dihydroguanine (8-oxoG), it does show strong preference for the products of its further oxidation: spiroiminodihydantoin and guanidinohydantoin. In addition to this MeNeil1_N domain, enzymes belonging to this family contain a helix-two turn-helix (H2TH) domain and a zincless finger motif. This characteristic "zincless finger" motif, is a structural equivalent of the zinc finger common to other members of the Fpg/Nei family. Neil1 is one of three homologs found in eukaryotes and its lineage extends back as far as early metazoans.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 1207734453   1 MPEGPELHLASQFVNEACRALVFGGCVEKSSVSRNPE 37
Cdd:cd08967     1 MPEGPELHLASLFVNKMCKGLIFTGAVEKSSVSKNPE 37

endonuclease VIII; Provisional

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1207734453  44 ENVLRNLADKAF-DRPICEALLDQRFFNGIGNYLRAEILYRLKIPPfekarsvlealqQHRPSpELTLSQ 112
Cdd:PRK10445  138 EQVKERLLSPRFrNRQFSGLLLDQAFLAGLGNYLRVEILWQAGLTP------------QHKAK-DLNEAQ 194

DNA-formamidopyrimidine glycosylase; All proteins in the FPG family with known functions are FAPY-DNA glycosylases that function in base excision repair. Homologous to endonuclease VIII (nei). This family is based on the phylogenomic analysis of JA Eisen (1999, Ph.D. Thesis, Stanford University). [DNA metabolism, DNA replication, recombination, and repair]

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 1207734453  57 RPICEALLDQRFFNGIGNYLRAEILYRLKIPPFEKARSV 95
Cdd:TIGR00577 156 RKIKTALLDQRLVAGIGNIYADEVLFRAGIHPERLASSL 194

N-terminal domain of metazoan Nei-like glycosylase 1 (NEIL1); This family contains the N-terminal domain of metazoan NEIL1. It belongs to the FpgNei_N, [N-terminal domain of Fpg (formamidopyrimidine-DNA glycosylase, MutM)_Nei (endonuclease VIII)] domain superfamily. DNA glycosylases maintain genome integrity by recognizing base lesions created by ionizing radiation, alkylating or oxidizing agents, and endogenous reactive oxygen species. They initiate the base-excision repair process, which is completed with the help of enzymes such as phosphodiesterases, AP endonucleases, DNA polymerases and DNA ligases. DNA glycosylases cleave the N-glycosyl bond between the sugar and the damaged base, creating an AP (apurinic/apyrimidinic) site. Most FpgNei DNA glycosylases use their N-terminal proline residue as the key catalytic nucleophile, and the reaction proceeds via a Schiff base intermediate. NEIL1 recognizes the oxidized pyrimidines 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG) and 4,6-diamino- 5-formamidopyrimidine (FapyA), thymine glycol (Tg) and 5-hydroxyuracil (5-OHU). However, even though it has weak activity on 8-oxo-7,8-dihydroguanine (8-oxoG), it does show strong preference for the products of its further oxidation: spiroiminodihydantoin and guanidinohydantoin. In addition to this MeNeil1_N domain, enzymes belonging to this family contain a helix-two turn-helix (H2TH) domain and a zincless finger motif. This characteristic "zincless finger" motif, is a structural equivalent of the zinc finger common to other members of the Fpg/Nei family. Neil1 is one of three homologs found in eukaryotes and its lineage extends back as far as early metazoans.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 1207734453   1 MPEGPELHLASQFVNEACRALVFGGCVEKSSVSRNPE 37
Cdd:cd08967     1 MPEGPELHLASLFVNKMCKGLIFTGAVEKSSVSKNPE 37

endonuclease VIII; Provisional

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1207734453  44 ENVLRNLADKAF-DRPICEALLDQRFFNGIGNYLRAEILYRLKIPPfekarsvlealqQHRPSpELTLSQ 112
Cdd:PRK10445  138 EQVKERLLSPRFrNRQFSGLLLDQAFLAGLGNYLRVEILWQAGLTP------------QHKAK-DLNEAQ 194

DNA-formamidopyrimidine glycosylase; All proteins in the FPG family with known functions are FAPY-DNA glycosylases that function in base excision repair. Homologous to endonuclease VIII (nei). This family is based on the phylogenomic analysis of JA Eisen (1999, Ph.D. Thesis, Stanford University). [DNA metabolism, DNA replication, recombination, and repair]

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 1207734453  57 RPICEALLDQRFFNGIGNYLRAEILYRLKIPPFEKARSV 95
Cdd:TIGR00577 156 RKIKTALLDQRLVAGIGNIYADEVLFRAGIHPERLASSL 194