Outer capsid glycoprotein VP7, G4 genotype (Rotavirus VP7 G4) (VP7 G4)

Rotavirus VP7 G4 is the outer capsid glycoprotein of rotavirus genotype G4, organized as calcium-stabilized trimers that form the outermost layer of the rotavirus triple-layered particle (TLP)[1][2]. The protein consists of two domains: a Rossmann-fold domain (domain I) and a jelly-roll beta sandwich domain (domain II), connected by disordered N- and C-terminal arms[1]. VP7 is stabilized through calcium ion binding at subunit interfaces, with the N-terminal arms gripping the underlying VP6 trimer layer[1][2]. VP7 G4 serves as a principal target of protective neutralizing antibodies and is immunodominant in rotavirus infections and vaccination[1][3]. The protein contains two critical antigenic epitopes: region 7-1 (comprising subunits 7-1a and 7-1b) and region 7-2, located on the outward-facing surface of the trimer[1][3]. Neutralizing antibodies inhibit rotavirus infection by binding to these epitopes and stabilizing the VP7 trimer, thereby preventing the calcium-dependent uncoating process necessary for viral entry[1]. The VP7 G4 layer is structurally the stiffest and most elastic component of the rotavirus particle, with strong resistance to fatigue and high breaking force[2]. Circulating G4 rotavirus strains show substantial antigenic variation compared to vaccine strains, particularly in the 7-1b epitope region, with multiple amino acid differences and potential escape mutations that may reduce vaccine effectiveness[3]. This antigenic variation is a significant challenge for rotavirus vaccine development and strain surveillance programs.

Other names

Viral protein 7Rotavirus glycoprotein G4G4 rotavirus VP7Outer capsid protein VP7

Neutralizing antibodies bind to VP7 trimeric structure at the intersubunit junction (region 7-1), stabilizing the trimer and inhibiting the uncoating trigger required for VP4 rearrangement and membrane penetration. Calcium withdrawal destabilizes VP7 trimers, initiating uncoating and viral entry.