Structure of formamidopyrimidine-DNA glycosylase covalently complexed to DNA
Structure of formamidopyrimidine-DNA glycosylase covalently complexed to DNA
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DOI：
10.1074/jbc.m202058200
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发表时间：
2002-05-31
影响因子：
4.8
通讯作者：
Shoham, G
中科院分区：
文献类型：
--
作者：
Gilboa, R;Zharkov, DO;Shoham, G
甲基嘧啶-DNA糖基酶(FPG)是一种DNA修复酶，能从损伤的DNA中清除氧化的嘌呤。该反应生成的席夫碱中间体被硼氢化钠还原捕获，得到的共价交联络合物的结构被确定为2.1埃分辨率。FPG是一种双叶蛋白，具有宽的带正电的DNA结合槽。它具有一个保守的锌指和一个参与DNA结合的螺旋-两个旋转螺旋基序。绝对保守的残基Lys-56、His-70、Asn-168和Arg-258与DNA的磷酸二酯骨架形成氢键，在病变部位急剧扭曲。Met-73、Arg-109和Phe-110残基被插入DNA螺旋，填补了核苷酸外翻造成的空白。活性部位的深层疏水口袋被放置以容纳外翻的底座。对FPG-DNA复合体的结构分析揭示了损伤识别的基本特征和FPG的催化机理。
Formamidopyrimidine-DNA glycosylase (Fpg) is a DNA repair enzyme that excises oxidized purines from damaged DNA. The Schiff base intermediate formed during this reaction between Escherichia coli Fpg and DNA was trapped by reduction with sodium borohydride, and the structure of the resulting covalently cross-linked complex was determined at a 2.1-Angstrom resolution. Fpg is a bilobal protein with a wide, positively charged DNA-binding groove. It possesses a conserved zinc finger and a helix-two turn-helix motif that participate in DNA binding. The absolutely conserved residues Lys-56, His-70, Asn-168, and Arg-258 form hydrogen bonds to the phosphodiester backbone of DNA, which is sharply kinked at the lesion site. Residues Met-73, Arg-109, and Phe-110 are inserted into the DNA helix, filling the void created by nucleotide eversion. A deep hydrophobic pocket in the active site is positioned to accommodate an everted base. Structural analysis of the Fpg-DNA complex reveals essential features of damage recognition and the catalytic mechanism of Fpg.