Structural basis for the regulatory function of a complex zinc-binding domain in a replicative arterivirus helicase resembling a nonsense-mediated mRNA decay helicase

Deng, Zengqin; Lehmann, Kathleen C.; Li, Xiaorong; Feng, Chong; Wang, Guoqiang; Zhang, Qi; Qi, Xiaoxuan; Yu, Lin; Zhang, Xingliang; Feng, Wenhai; Wu, Wei; Gong, Peng; Tao, Ye; Posthuma, Clara C.; Snijder, Eric J.; Gorbalenya, Alexander E.; Chen, Zhongzhou

The observed structural affinity between the EAV nsp10 and Upf1 helicases is most remarkable, in particular because it extends to include the multi-domain organization essential for helicase function. This organization is only found in Upf1 of all eukaryotes (59) and nidovirus helicases (19, 24, 25, 28) . For Upf1, its conservation was linked to the protein's universal role in posttranscriptional quality control of eukaryotic RNAs through multiple pathways, including nonsense-mediated mRNA decay (54) (55) (56) . Upf1 interacts, commonly through its C/H and 1A domains, with proteins that can modulate its function. For the nidovirus helicase subunit, the functional basis of its domain conservation remains to be firmly established, although ZBD-like C/H in Upf1 (63)-affects helicase activity (36, 37) .