Characterization of Escherichia coli endonuclease VIII
Characterization of Escherichia coli endonuclease VIII
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DOI：
10.1074/jbc.272.51.32230
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发表时间：
1997-12-19
影响因子：
4.8
通讯作者：
Wallace, SS
中科院分区：
文献类型：
--
作者：
Jiang, DY;Hatahet, Z;Wallace, SS
大肠杆菌核酸内切酶VIII(Endo VIII)与核酸内切酶III(Endo III)一样，能从双链质粒或噬菌体DNA中去除胸腺嘧啶的辐射裂解产物，包括胸腺嘧啶二醇、二氢胸腺嘧啶、β-脲异丁酸和尿素，并在碱基(AP)处切割DNA链(Melameed，R.J.，Hatahet，Z.，Kow，Y.W.，Ide.，H.，and Wallace，S.(1994)BioChemic33,1255-1264)。使用明显均一的Endo Vm蛋白，我们现在证明了Endo MI从双链寡核苷酸中去除了胞嘧啶、5-羟基胞嘧啶和5-羟基尿嘧啶的稳定氧化产物。远藤通过β-、β-消除和甲酰胺基嘧啶脱氧核糖基酶一样切割损伤的DNA链。与FPG一样，Endo VIII也从内切酶IV(Endo TV)预切的AP位点上切下5‘端脱氧核糖磷酸。因此，除了氨基酸序列同源性(酱，D.，Hatahet，Z.，Blaisdell，J.，Melamed，R.J.和Wallace，S.S.(1997)J.Billiol 179,3773-3782)外，Endo VIII与FPG具有许多催化性质。此外，Endo WI与含有还原AP位点的寡聚脱氧核苷酸特异性结合，蛋白质与DNA的化学计量比为1：1，表观平衡解离常数为3.9 nM。与FPG和Endo III一样，DNase I的足迹很小，接触位点主要在含有损伤的链上；与FPG和Endo III不同的是，Endo VIII与DNA的DNA结合是不对称的，3‘与还原的AP位点结合。
Escherichia coli endonuclease VIII (endo VIII) was identified as an enzyme that, like endonuclease III (endo III), removes radiolysis products of thymine including thymine glycol, dihydrothymine, beta-ureidoisobutyric acid, and urea from double-stranded plasmid or phage DNA and cleaves the DNA strand at abasic (AP) sites (Melamede, R. J., Hatahet, Z., Kow, Y. W., Ide., H., and Wallace, S. S. (1994) Biochemistry 33, 1255-1264). Using apparently homogeneous endo Vm protein, we now show that endo MI removes from double-stranded oligodeoxyribonucleotides the stable oxidative products of cytosine, 5-hydroxycytosine and 5-hydroxyuracil. Endo VIII cleaved the damage-containing DNA strand by beta,delta-elimination as does formamidopyrimidine DNA glycosylase (Fpg). Like Fpg, endo VIII also excised the 5'-terminal deoxyribose phosphate from an endonuclease IV (endo TV) pre-incised AP site. Thus, in addition to amino acid sequence homology (Jiang, D., Hatahet, Z., Blaisdell, J., Melamede, R. J., and Wallace, S. S. (1997) J. Bacteriol 179, 3773-3782), endo VIII shares a number of catalytic properties with Fpg. In addition, endo WI specifically bound to oligodeoxynucleotides containing a reduced AP site with a stoichiometry of 1:1 for protein to DNA with an apparent equilibrium dissociation constant of 3.9 nM. Like Fpg and endo III, the DNase I footprint was small with contact sites primarily on the damage-containing strand; unlike Fpg and endo III, the DNA binding of endo VIII to DNA was asymmetric, 3' to the reduced AP site.