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In molecular biology the protein domain XPG refers to, in this case, the N-terminus of XPG. The XPG protein can be corrected by a 133 kDa nuclear protein, XPGC. XPGC is an acidic protein that confers normal ultraviolet (UV) light resistance. It is a magnesium-dependent, single-strand DNA endonuclease that makes structure-specific endonucleolytic incisions in a DNA substrate containing a duplex region and single-stranded arms.〔 XPGC cleaves one strand of the duplex at the border with the single-stranded region.〔 ==Homology== XPG belongs to a family of proteins that includes: * RAD2 from ''Saccharomyces cerevisiae'' (Baker's yeast) and rad13 from ''Schizosaccharomyces pombe'' (Fission yeast), which are single-stranded DNA endonucleases,;〔 * mouse and human FEN-1, a structure-specific endonuclease; * RAD2 from fission yeast and RAD27 from budding yeast; * fission yeast exo1, a 5'-3' double-stranded DNA exonuclease that may act in a pathway that corrects mismatched base pairs; * yeast DHS1, * yeast DIN7. Sequence alignment of this family of proteins reveals that similarities are largely confined to two regions. The first is located at the N-terminal extremity (N-region) and corresponds to the first 95 to 105 amino acids. The second region is internal (I-region) and found towards the C terminus; it spans about 140 residues and contains a highly conserved core of 27 amino acids that includes a conserved pentapeptide (E-A-()-A-()). It is possible that the conserved acidic residues are involved in the catalytic mechanism of DNA excision repair in XPG. The amino acid linking the N- and I-regions are not conserved. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「XPG N terminus」の詳細全文を読む スポンサード リンク
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