FIG 3.

Schematic illustration of the HMPV particle showing the molecular scaffolding assembled in the host cell lipid bilayer. Three different viral proteins are embedded: the F protein (orange) (a trimer) (265), the G protein (green) (a tetramer), and the SH protein (red) (a pentamer). The viral matrix (blue) encapsulates the nucleoprotein-associated genome (yellow-green) or nucleocapsid underneath the lipid bilayer. Similarly to HRSV, the nucleocapsid of HMPV is thought to form long helical structures that are packaged within the viral particle (86, 88). The ribonucleoprotein complex is associated with the L protein (yellow), along with its cofactors (P [violet] [a tetramer] [266] and the M2-1 protein [pale blue] [a tetramer] [100, 101]). It is thought that as part of the TR complex, the M2-2 protein (pale blue) is also included within viral particles.