Capsid protein of Enterovirus D68

The **capsid protein of Enterovirus D68 (EV-D68)** comprises an icosahedral shell encapsulating the viral RNA genome, formed by 60 copies each of the structural proteins **VP1, VP2, VP3**, and **VP4**[6][7][10]. These proteins assemble into protomers (VP1-VP4), further forming the mature viral capsid (about 30 nm diameter)[1][4]. The outer surface is composed mainly of VP1–VP3, with a unique canyon structure surrounding the fivefold axes that serves as a primary site for host receptor binding (notably **sialic acid** and **ICAM-5**)[1][2]. VP4 is internal, associated with the capsid interior and genome. The capsid undergoes conformational changes upon receptor binding or acidification, facilitating viral uncoating and genome release[1][7]. This protein complex is considered a therapeutic target for antivirals such as pleconaril (which binds to and stabilizes the capsid, blocking uncoating) and for neutralizing antibodies that block receptor engagement or induce premature uncoating[10][1]. The capsid is also a key antigenic target for vaccine development and host immune responses against EV-D68; changes in capsid structure or sequence may influence viral pathogenesis, immune escape, and resistance to therapy.

Other names

EV-D68 capsid proteinEnterovirus D68 capsidStructural proteins VP1–VP4 of EV-D68

Inhibition of viral attachment to host receptors by blocking the canyon or other capsid sites[1][3] Stabilization of the capsid to prevent conformational transitions required for uncoating[10] Premature triggering of uncoating transitions leading to noninfectious particles