2OY0

Crystal structure of the West Nile virus methyltransferase

2OY0 の概要

• エントリーDOI: 10.2210/pdb2oy0/pdb
• 分子名称: Methyltransferase, S-ADENOSYL-L-HOMOCYSTEINE (3 entities in total)
• 機能のキーワード: wnv, methyltransferase, n-7, 2'-o, flavivirus, viral protein
• 由来する生物種: West Nile virus
• 細胞内の位置: Envelope protein E: Virion membrane; Multi- pass membrane protein: Q9Q6P4
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 60885.67

構造登録者

Li, H.M.,Zhao, Y.W.,Guo, Y.,Shi, P.Y. (登録日: 2007-02-21, 公開日: 2007-04-03, 最終更新日: 2023-08-30)

主引用文献

Zhou, Y.,Ray, D.,Zhao, Y.,Dong, H.,Ren, S.,Li, Z.,Guo, Y.,Bernard, K.A.,Shi, P.Y.,Li, H.
Structure and Function of Flavivirus NS5 Methyltransferase.
J.Virol., 81:3891-3903, 2007

PubMed Abstract: The plus-strand RNA genome of flavivirus contains a 5' terminal cap 1 structure (m7GpppAmG). The flaviviruses encode one methyltransferase, located at the N-terminal portion of the NS5 protein, to catalyze both guanine N-7 and ribose 2'-OH methylations during viral cap formation. Representative flavivirus methyltransferases from dengue, yellow fever, and West Nile virus (WNV) sequentially generate GpppA-->m7GpppA-->m7GpppAm. The 2'-O methylation can be uncoupled from the N-7 methylation, since m7GpppA-RNA can be readily methylated to m7GpppAm-RNA. Despite exhibiting two distinct methylation activities, the crystal structure of WNV methyltransferase at 2.8 A resolution showed a single binding site for S-adenosyl-L-methionine (SAM), the methyl donor. Therefore, substrate GpppA-RNA should be repositioned to accept the N-7 and 2'-O methyl groups from SAM during the sequential reactions. Electrostatic analysis of the WNV methyltransferase structure showed that, adjacent to the SAM-binding pocket, is a highly positively charged surface that could serve as an RNA binding site during cap methylations. Biochemical and mutagenesis analyses show that the N-7 and 2'-O cap methylations require distinct buffer conditions and different side chains within the K61-D146-K182-E218 motif, suggesting that the two reactions use different mechanisms. In the context of complete virus, defects in both methylations are lethal to WNV; however, viruses defective solely in 2'-O methylation are attenuated and can protect mice from later wild-type WNV challenge. The results demonstrate that the N-7 methylation activity is essential for the WNV life cycle and, thus, methyltransferase represents a novel target for flavivirus therapy.

PubMed: 17267492
DOI: 10.1128/JVI.02704-06

実験手法

X-RAY DIFFRACTION (2.8 Å)