7V1H

Crystal structure of Omsk hemorrhagic fever virus NS5 MTase (in complex with SAM and m7GTP)

7V1H の概要

• エントリーDOI: 10.2210/pdb7v1h/pdb
• 分子名称: Core protein, 7-METHYL-GUANOSINE-5'-TRIPHOSPHATE, GLYCEROL, ... (8 entities in total)
• 機能のキーワード: guanylyltransferase, methyltransferase, viral protein, transferase
• 由来する生物種: Omsk hemorrhagic fever virus (OHFV)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 31299.68

構造登録者

Jia, H.,Gong, P. (登録日: 2021-08-04, 公開日: 2022-06-15, 最終更新日: 2023-11-29)

主引用文献

Jia, H.,Zhong, Y.,Peng, C.,Gong, P.
Crystal Structures of Flavivirus NS5 Guanylyltransferase Reveal a GMP-Arginine Adduct.
J.Virol., 96:e0041822-e0041822, 2022

PubMed Abstract: The positive-sense flavivirus RNA genome bears a cap 1 structure essential for RNA stability and viral protein translation, and the formation of cap 1 requires the virally encoded nonstructural protein NS5 harboring guanylyltransferase (GTase), cap guanine N7 methyltransferase (N7 MTase), and 5'-nucleotide ribose 2'-O MTase activities in its single-domain MTase module. Despite numerous MTase-containing structures reported, the structural evidence for a critical GMP-enzyme intermediate formation and RNA repositioning when transitioning among different reactions is missing. Here, we report 10 high-resolution MTase crystal structures of Omsk hemorrhagic fever virus (OHFV), a representative high-consequence tick-borne flavivirus, capturing previously unidentified GMP-arginine adduct structures and a rarely observed capped RNA conformation. These structures help us thread capping events in the canonical model with a structure-based hypothesis involving the flipping of the 5' nucleotide, while the observation of an mGMP-arginine adduct is compatible with an alternate capping model that decouples the N7 and 2'-O methylation steps. The methyltransferase (MTase) domain of flavivirus NS5 is unique in harboring guanylyltransferase (GTase), N7 MTase, and 2'-O MTase activities, playing a central role in viral RNA capping. However, the detailed mechanisms of the multistep capping process remain elusive. Here, we report 10 crystal structures of a flavivirus MTase to help understand the guanylyl transfer from GTP to the GTase itself and the transition between guanylyl transfer and methylation steps. In particular, a previously unobserved GMP-arginine covalent intermediate was captured multiple times in MTase crystal soaking trials with GTP present in the soaking solution, supporting its role in bridging the guanylyl transfer from GTP to the GTase and subsequent transfer to the 5'-diphosphate RNA.

PubMed: 35758665
DOI: 10.1128/jvi.00418-22

実験手法

X-RAY DIFFRACTION (2 Å)