Cryo-EM Structure of Chikungunya Virus in Complex with the Mxra8 Receptor

Abstract

Basore et al. describe an X-ray crystal structure of Mxra8, an entry receptor for arthritogenic alphaviruses, and cryo-EM structures of Mxra8 bound to CHIKV. Mxra8 has an unusual Ig-like domain architecture with a head-to-head arrangement, with domain 1 emanating from a loop of domain 2. Mxra8 binds into a complex quaternary cleft formed between two E2-E1 heterodimers within a trimeric spike, while also contacting E1 from a neighboring spike. Mxra8 occupancy is lower when E3 protein is retained on the virion.