Structural basis of the monkeypox virus mRNA cap N7 methyltransferase complex

Anke Chen; Ning Fang; Zhifei Zhang; Yiqing Wen; Yajie Shen; Yanjie Zhang; Lu Zhang; Guoping Zhao; Jin Ding; Jixi Li

doi:10.1080/22221751.2024.2369193

Structural basis of the monkeypox virus mRNA cap N7 methyltransferase complex

Emerg Microbes Infect. 2024 Dec;13(1):2369193. doi: 10.1080/22221751.2024.2369193. Epub 2024 Jun 27.

Authors

Anke Chen¹, Ning Fang¹, Zhifei Zhang¹, Yiqing Wen¹, Yajie Shen¹, Yanjie Zhang², Lu Zhang³, Guoping Zhao^{3

4}, Jin Ding², Jixi Li^{1

5}

Affiliations

¹ State Key Laboratory of Genetic Engineering, School of Life Sciences and Huashan Hospital, Shanghai Engineering Research Center of Industrial Microorganisms, Fudan University, Shanghai, People's Republic of China.
² Clinical Cancer Institute, Center for Translational Medicine, Naval Medical University, Shanghai, People's Republic of China.
³ State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, People's Republic of China.
⁴ Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, People's Republic of China.
⁵ Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, People's Republic of China.

Abstract

The global outbreak of Mpox, caused by the monkeypox virus (MPXV), has attracted international attention and become another major infectious disease event after COVID-19. The mRNA cap N7 methyltransferase (RNMT) of MPXV methylates the N7 position of the added guanosine to the 5'-cap structure of mRNAs and plays a vital role in evading host antiviral immunity. MPXV RNMT is composed of the large subunit E1 and the small subunit E12. How E1 and E12 of MPXV assembly remains unclear. Here, we report the crystal structures of E12, the MTase domain of E1 with E12 (E1_CTD-E12) complex, and the E1_CTD-E12-SAM ternary complex, revealing the detailed conformations of critical residues and the structural changes upon E12 binding to E1. Functional studies suggest that E1_CTD N-terminal extension (Asp545-Arg562) and the small subunit E12 play an essential role in the binding process of SAM. Structural comparison of the AlphaFold2-predicted E1, E1_CTD-E12 complex, and the homologous D1-D12 complex of vaccinia virus (VACV) indicates an allosteric activating effect of E1 in MPXV. Our findings provide the structural basis for the MTase activity stimulation of the E1-E12 complex and suggest a potential interface for screening the anti-poxvirus inhibitors.

Keywords: Monkeypox virus; SAXS; mRNA cap N7 methyltransferase; protein complex; structure.

MeSH terms

Crystallography, X-Ray
Humans
Methyltransferases* / chemistry
Methyltransferases* / genetics
Methyltransferases* / metabolism
Models, Molecular
Monkeypox virus* / chemistry
Monkeypox virus* / enzymology
Monkeypox virus* / genetics
Protein Binding
Protein Conformation
RNA Caps / chemistry
RNA Caps / metabolism
RNA, Messenger / chemistry
RNA, Messenger / genetics
RNA, Messenger / metabolism
Viral Proteins / chemistry
Viral Proteins / genetics
Viral Proteins / metabolism

Substances

Methyltransferases
Viral Proteins
RNA Caps
RNA, Messenger

Grants and funding

This work was supported by Ministry of Science and Technology of the People's Republic of China: [grant no 2021YFC2301500]; the National Key Research and Development Project of China [grant no 2021YFC2301500]; the National Natural Science Foundation of China [grant no 32161160323].