Imura Tomoki, Hosokawa Yuhei, Yang Kai Chun, Ban Yuki, Shih Hsuan Yu, Yamamoto Junpei, Maestre-Reyna Manuel
Division of Chemistry, Graduate School of Engineering Science, University of Osaka, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
Department of Chemistry, National Taiwan University, 1 Roosevelt Road, Sec. 4, Taipei 106, Taiwan.
IUCrJ. 2025 Sep 1;12(Pt 5):515-522. doi: 10.1107/S2052252525006062.
Co-crystal structures of a base-excision DNA-repair enzyme (human 8-oxoguanine DNA glycosylase; hOgg1) in complex with a photocaged 8-oxoguanine DNA lesion were determined before and after uncaging via illumination at 2.81 and 2.48 Å resolution, respectively. The structures were carefully reassessed to rapidly expand the target repertoire of light-triggered time-resolved macromolecular crystallography. Late-intermediate cryo-trapping after uncaging revealed the partial accommodation of 8-oxoguanine in the active site with 68% occupancy, which did not induce full active-site adaptation to the catalytic state. Crystal illumination led to a light-dependent loss of diffraction power, likely due to crystal-packing collapse during the very late reaction stages. This work therefore not only demonstrates that hOgg1 is well suited for time-resolved crystallography, but also that such analysis is necessary to determine further steps in its reaction.
通过分别在2.81 Å和2.48 Å分辨率下进行光照解笼前后，测定了一种碱基切除DNA修复酶（人8-氧代鸟嘌呤DNA糖基化酶；hOgg1）与光笼化8-氧代鸟嘌呤DNA损伤复合物的共晶体结构。对这些结构进行了仔细重新评估，以快速扩展光触发时间分辨大分子晶体学的目标库。解笼后的晚期中间体低温捕获揭示了8-氧代鸟嘌呤在活性位点的部分容纳，占有率为68%，这并未诱导活性位点完全适应催化状态。晶体光照导致衍射能力的光依赖性损失，这可能是由于在非常晚期的反应阶段晶体堆积崩溃所致。因此，这项工作不仅表明hOgg1非常适合时间分辨晶体学，而且还表明这种分析对于确定其反应的进一步步骤是必要的。
