Starostenko L V, Maltseva E A, Lebedeva N A, Pestryakov P E, Lavrik O I, Rechkunova N I
Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
Biochemistry (Mosc). 2016 Mar;81(3):233-41. doi: 10.1134/S0006297916030056.
The combined action of reactive metabolites of benzo[a]pyrene (B[a]P) and oxidative stress can lead to cluster-type DNA damage that includes both a bulky lesion and an apurinic/apyrimidinic (AP) site, which are repaired by the nucleotide and base excision repair mechanisms - NER and BER, respectively. Interaction of NER protein XPC-RAD23B providing primary damage recognition with DNA duplexes containing a B[a]P-derived residue linked to the exocyclic amino group of a guanine (BPDE-N(2)-dG) in the central position of one strand and AP site in different positions of the other strand was analyzed. It was found that XPC-RAD23B crosslinks to DNA containing (+)-trans-BPDE-N(2)-dG more effectively than to DNA containing cis-isomer, independently of the AP site position in the opposite strand; protein affinity to DNA containing one of the BPDE-N(2)-dG isomers depends on the AP site position in the opposite strand. The influence of XPC-RAD23B on hydrolysis of an AP site clustered with BPDE-N(2)-dG catalyzed by the apurinic/apyrimidinic endonuclease 1 (APE1) was examined. XPC-RAD23B was shown to stimulate the endonuclease and inhibit the 3'-5' exonuclease activity of APE1. These data demonstrate the possibility of cooperation of two proteins belonging to different DNA repair systems in the repair of cluster-type DNA damage.
苯并[a]芘（B[a]P）的反应性代谢产物与氧化应激的联合作用可导致簇状DNA损伤，其中包括一个大的损伤和一个无嘌呤/无嘧啶（AP）位点，它们分别通过核苷酸切除修复机制（NER）和碱基切除修复机制（BER）进行修复。分析了提供主要损伤识别功能的NER蛋白XPC-RAD23B与DNA双链体的相互作用，该双链体中一条链的中心位置含有与鸟嘌呤的外环氨基相连的B[a]P衍生残基（BPDE-N(2)-dG），另一条链的不同位置含有AP位点。结果发现，XPC-RAD23B与含有（+）-反式-BPDE-N(2)-dG的DNA交联比与含有顺式异构体的DNA更有效，与相反链上AP位点的位置无关；蛋白质对含有BPDE-N(2)-dG异构体之一的DNA的亲和力取决于相反链上AP位点的位置。研究了XPC-RAD23B对无嘌呤/无嘧啶内切酶1（APE1）催化的与BPDE-N(2)-dG聚集的AP位点水解的影响。结果表明，XPC-RAD23B可刺激内切酶活性并抑制APE1的3'-5'外切酶活性。这些数据证明了属于不同DNA修复系统的两种蛋白质在修复簇状DNA损伤中协同作用的可能性。
