Viral protein class

glycoprotein spike on a viral capsid or viral envelope

thumb|right|The transmembrane helical tetramer of the [[influenza A virus M2 protein, which functions as a proton channel, in complex with the channel-blocking drug amantadine (shown in red). Highly conserved tryptophan and histidine residues known to play key roles in mediating proton transport are shown as sticks. From .]] Viroporins are small and usually hydrophobic multifunctional viral proteins that modify cellular membranes, thereby facilitating virus release from infected cells. Viroporins are capable of assembling into oligomeric ion channels or pores in the host cell's membrane, rende