Crystal Structure of the C-Terminal Cytoplasmic Domain of Non-Structural Protein 4 from Mouse Hepatitis Virus A59

Xu, Xiaoling; Lou, Zhiyong; Ma, Yanlin; Chen, Xuehui; Yang, Zhangsheng; Tong, Xiaohang; Zhao, Qi; Xu, Yuanyuan; Deng, Hongyu; Bartlam, Mark; Rao, Zihe

The monomer structure of WT nsp4C. The WT nsp4C monomer contains four a-helices (a1-a4) and two short b-strands (b1-b2). The N-terminal starts from a short a-helix (a1, T408-T415), followed by a short b-strand (b1, T416-T420) connecting a1 and another short a-helix (a2, E422-S430), which is connected to a long a-helix (a3, S432-Y446) by a short loop. Notably, a long loop connects helix a3 and another long a-helix (a4, D454-N474); a-helices a3 and a4 point towards each other, and the loop connecting them enables a4 to turn to the back of a3 and connect by a short loop to b-strand b2 (b2, D480-Q484). The strands b2 and b1 are anti-parallel, while b2 is extending further via a long loop to the C-terminus of the molecule (Fig. 1) .