Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, PR China.
Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation, School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha, Hunan, 410004, PR China.
Talanta. 2022 Mar 1;239:123081. doi: 10.1016/j.talanta.2021.123081. Epub 2021 Nov 18.
Cyclobutane pyrimidine dimers (CPDs) are the major DNA photoproducts of thymine-thymine dinucleotides upon ultraviolet (UV) irradiation. Failure in the repair of damaged DNA may lead to DNA replication errors, DNA mutations, and even cell death. Photoreactivation can mediate the repair of UV-induced DNA lesions by photolyases upon UVA (315-400 nm) or blue light (400-500 nm) irradiation. Herein, the UVC (254 nm)-induced DNA damage and photoenzymatic repair of the CPD products were simultaneously monitored by electrochemical impedance spectroscopy (EIS). The UVC-damaged dT was first immobilized on the gold electrode, and the specific recognition by the anti-CPD antibody leads to significantly increased EIS signals. The electron transfer resistance (R) values were linearly proportional to the concentrations of damaged dT ranging from 0.005 to 0.1 μM, and a detection limit of 3.06 nM was achieved. Using surface plasmon resonance, the equilibrium dissociation constant (K) between the CPDs in dT and anti-CPD antibody was estimated to be (3.32 ± 0.31) × 10 M, indicating the strong binding affinity. Evidenced by EIS, the CPDs in the damaged dT could be repaired by the attached DNA photolyase under UVA (365 nm) photoexcitation, and the detachment of the photolyase from the DNA strand was accomplished after completion of the repair process. The repair efficiency was calculated to be 70.0% by EIS, being consistent with that of 71.4% by UV spectroscopy. The electrochemical method is simple, sensitive and straightforward, holding great potential for assaying other types of DNA lesions and their repair processes.
环丁烷嘧啶二聚体 (CPD) 是胸腺嘧啶-胸腺嘧啶二核苷酸在紫外线 (UV) 照射下产生的主要 DNA 光产物。如果不能修复受损的 DNA，可能会导致 DNA 复制错误、DNA 突变，甚至细胞死亡。光复活酶可以介导 UVA（315-400nm）或蓝光（400-500nm）照射下的光解酶对 UV 诱导的 DNA 损伤的修复。在此，通过电化学阻抗谱 (EIS) 同时监测了 UVC（254nm）诱导的 DNA 损伤和 CPD 产物的光酶修复。首先将 UVC 损伤的 dT 固定在金电极上，抗 CPD 抗体的特异性识别导致 EIS 信号显著增加。电子转移电阻 (R) 值与受损 dT 的浓度呈线性关系，范围为 0.005 至 0.1 μM，检测限为 3.06 nM。通过表面等离子体共振，估算出 dT 中 CPD 与抗 CPD 抗体之间的平衡解离常数 (K) 为 (3.32±0.31)×10 M，表明结合亲和力很强。通过 EIS 证明，在 UVA（365nm）光激发下，附着的 DNA 光解酶可以修复受损 dT 中的 CPD，并且在修复过程完成后，光解酶从 DNA 链上脱离。通过 EIS 计算得到的修复效率为 70.0%，与通过紫外光谱法得到的 71.4%一致。电化学方法简单、灵敏、直接，在检测其他类型的 DNA 损伤及其修复过程方面具有很大的潜力。
