...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Effects of benzo(a)pyrene adduct stereochemistry on downstream DNA replication in vitro: evidence for different adduct conformations within the active site of DNA polymerase I (Klenow fragment).
【24h】

Effects of benzo(a)pyrene adduct stereochemistry on downstream DNA replication in vitro: evidence for different adduct conformations within the active site of DNA polymerase I (Klenow fragment).

机译：苯并（a）re加合物立体化学对体外下游DNA复制的影响：DNA聚合酶I（Klenow片段）活性位点内不同加合物构象的证据。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The presence of bulky adducts in DNA is known to interfere with DNA replication not only at the site of the lesion but also at positions up to 5 nucleotides past the adduct location. Kinetic studies of primer extension by exonuclease-deficient E. coli DNA polymerase I (Klenow fragment) (KF) when (+)-trans- or (+)-cis-B[a]P-N(2)-dG adducts were positioned in the double-stranded region of the primer-templates showed that both stereoisomers significantly block downstream replication. However the (+)-cis adduct, which causes a stronger inhibition of the nucleotides insertion across from and immediately past the lesion, affected the downstream replication to a much smaller extent than did the (+)-trans adduct, especially when the B[a]P-modified dG was properly paired with a dC. The effects of mismatches across from the adduct and the sequence context surrounding the adduct were also dependent on the stereochemistry of the B[a]P adduct. Thus, the identity of the nucleotide across from the adduct that provided the best downstream replication was different for the (+)-cis and (+)-trans adducts, a factor that might differentially contribute to the mutagenic bypass of these lesions. These findings provide strong direct evidence that the conformations of the (+)-cis and (+)-trans adducts within the active site of KF are significantly different and probably differentially affect the interactions of the polymerase with the minor groove, thereby leading to different replication trends. The stereochemistry of the adduct was also found to differentially affect the sequence-mediated primer-template misalignments, resulting in different consequences during the bypass of the lesion.
机译：众所周知，DNA中大量加合物的存在不仅会影响病变部位，而且还会超过加合物位置最多5个核苷酸的位置干扰DNA复制。当（+）-反式或（+）-顺式-B [a] PN（2）-dG加成物位于以下位置时，通过核酸外切酶缺陷型大肠杆菌DNA聚合酶I（Klenow片段）（KF）进行引物延伸的动力学研究引物模板的双链区显示两种立体异构体均显着阻断下游复制。然而，（+）-顺式加合物可更强地抑制从病变处穿过和穿过病变部位的核苷酸插入，与（+）-反式加合物相比，对下游复制的影响程度要小得多，尤其是当B [-] a] P修饰的dG与dC正确配对。加合物两端的错配和围绕加合物的序列背景的影响也取决于B [a] P加合物的立体化学。因此，提供最佳下游复制的加合物对面核苷酸的身份对于（+）-顺式和（+）-反式加合物而言是不同的，这可能会导致这些病变的诱变旁路不同。这些发现提供了有力的直接证据，表明KF活性位点内的（+）-顺式和（+）-反式加合物的构型显着不同，并可能差异地影响聚合酶与小沟的相互作用，从而导致不同的复制趋势。还发现加合物的立体化学差异地影响序列介导的引物-模板错位，从而在绕过病变期间导致不同的后果。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号