Structural basis of DNA replication fidelity of the Mpox virus

• 成果类型: Article
• 署名作者: Xie, Yufeng; Kuai, Lu; Peng, Qi; Wang, Qian; Wang, Han; Li, Xiaomei; Qi, Jianxun; Ding, Qiang; Shi, Yi; Gao, George F.
• 署名单位: Tsinghua University; Chinese Academy of Sciences; Institute of Microbiology, CAS; Peking University; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Chinese Academy of Sciences; Chinese Academy of Medical Sciences - Peking Union Medical College
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9673
• DOI: 10.1073/pnas.2411686122
• 发表日期: 2025-03-11
• 关键词: exonuclease activity; crystal-structure; excision-repair; glycosylase; polymerase; complex; Visualization; inactivation; protein

摘要

The Mpox virus (MPXV) is an orthopoxvirus that caused a global outbreak in 2022. The poxvirus DNA polymerase complex is responsible for the replication and integrity of the viral genome; however, the molecular mechanisms underlying DNA replication fidelity are still unclear. In this study, we determined the cryoelectron microscopy (cryo-EM) structures of the MPXV F8-A22-E4 polymerase holoenzyme in its editing state, in complex with mismatched primer-template DNA and DNA containing uracil deoxynucleotide. We showed that the MPXV polymerase has a similar replication-to-edit transition mechanism to proofread the mismatched nucleotides like the B-family DNA polymerases of other species. The unique processivity cofactor A22-E4 undergoes conformational changes in different working states and might affect the proofreading process. Moreover, we elucidated the base excision repair (BER) function of E4 as uracil-DNA glycosylase and the coupling mechanism of genome replication and BER, characteristic of poxviruses. Our findings greatly enhance our molecular understanding of DNA replication fidelity of orthopoxviruses and will stimulate the development broad-spectrum antiviral drugs.