Rate of incision of N-acetyl-2-aminofluorene and N-2-aminofluorene adducts by UvrABC nuclease is adduct- and sequence-specific:: Comparison of the rates of UvrABC nuclease incision and protein-DNA complex formation
Rate of incision of N-acetyl-2-aminofluorene and N-2-aminofluorene adducts by UvrABC nuclease is adduct- and sequence-specific:: Comparison of the rates of UvrABC nuclease incision and protein-DNA complex formation
复制标题
DOI：
10.1021/bi971544p
复制
发表时间：
1998-01-13
期刊：
影响因子：
2.9
通讯作者：
Romano, LJ
中科院分区：
文献类型：
--
作者：
Mekhovich, O;Tang, MS;Romano, LJ
UvrABC核酸酶是来自大肠杆菌的核苷酸切除修复复合物，能够切割多种类型的DNA损伤，并且该酶复合物的修复效率似乎受到损伤结构和损伤定位的序列背景的影响。为了更好地建立这些关系，我们构建了两个DNA序列，每个序列均含有位点特异性定位的N-2-氨基芴（AF）或N-乙酰基-2-氨基芴（AAF）加合物，并确定了UvrABC核酸酶切割的动力学和动力学UvrABC核酸酶-底物复合物形成。这两种加合物在DNA中诱导非常不同的结构，并且这些结构也取决于序列背景。我们发现，当AAF-和AF-DNA加合物位于突变热点NarI序列（5-GGCG*CC-3 '）时，它们的切割速率明显快于位于正常或非NarI序列（5'-GATG*ATA-3 '）时，并且AAF-DNA加合物的切割速率比两种序列中AF加合物的切割速率都快。最显著的是，我们发现UvrB和UvrBC-底物复合物形成的速率与UvrABC核酸酶切割的速率相关。
The UvrABC nuclease, the nucleotide excision repair complex from Escherichia coli, is able to incise a variety of types of DNA damage and the repair efficiency of this enzyme complex appears to be influenced by the structure of the damage and the sequence context within which the damage is positioned. In order to better establish these relationships, we have constructed two DNA sequences each containing a site-specifically positioned N-2-aminofluorene (AF) or N-acetyl-2-aminofluorene (AAF) adduct and have determined both the kinetics of UvrABC nuclease incision and the kinetics of UvrABC nuclease-substrate complex formation. It is well established that these two adducts induce very different structures in the DNA and that these structures also depend on the sequence context. We have found that the rate of incision of both AAF- and AF-DNA adducts is significantly faster when they are positioned in the mutation hotspot NarI sequence (5-GGCG*CC-3') than when located in a normal or non-NarI sequence (5'-GATG*ATA-3') and that the rate of incision for AAF-DNA adducts is faster that for AF adducts in both sequences. Most siginificantly, we find that the rate of UvrB and UvrBC-substrate complex formation correlates with the rate of UvrABC nuclease incision.