Liu Xipeng, Zhang Yang, Liang Rubing, Hou Jingli, Liu Jianhua
College of Life Sciences & Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Biochem Biophys Res Commun. 2007 Oct 5;361(4):987-93. doi: 10.1016/j.bbrc.2007.07.120. Epub 2007 Jul 31.
Endonuclease IV has AP endonuclease and 3'-repair diesterase activities. Here, we report Chlamydophila pneumoniae endonuclease IV (CpEndoIV) could hydrolyze the ds DNA and the RNA strand of RNA/DNA hybrid from the 3' end, yet the DNA strand of RNA/DNA hybrid was not the effective substrate of CpEndoIV. The optimal pH for 3' exonuclease on double-stranded (ds) DNA and RNA/DNA hybrids were both basic, but with some difference. The effect of divalent ions (Mg(2+), Ca(2+), Zn(2+), Cu(2+), Ni(2+), and Mn(2+)) on 3' exonuclease was different for both substrates. High concentration of NaCl inhibited 3' exonuclease on both substrates. For both substrates, the 3' exonuclease activity of CpEndoIV on matched and mismatched 3' end was comparable.
核酸内切酶IV具有脱嘌呤嘧啶核酸内切酶和3'-修复二酯酶活性。在此,我们报告肺炎衣原体核酸内切酶IV(CpEndoIV)能够从3'端水解双链DNA以及RNA/DNA杂交体的RNA链,但RNA/DNA杂交体的DNA链不是CpEndoIV的有效底物。双链(ds)DNA和RNA/DNA杂交体上3'外切核酸酶的最适pH均为碱性,但存在一些差异。二价离子(Mg(2+)、Ca(2+)、Zn(2+)、Cu(2+)、Ni(2+)和Mn(2+))对两种底物的3'外切核酸酶的影响不同。高浓度的NaCl抑制两种底物上的3'外切核酸酶。对于两种底物,CpEndoIV在匹配和错配3'端的3'外切核酸酶活性相当。