The native structure of the assembled matrix protein 1 of influenza A virus.

Influenza A virus causes millions of severe cases of disease during annual epidemics. The most abundant protein in influenza virions is matrix protein 1 (M1), which mediates virus assembly by forming an endoskeleton beneath the virus membrane. The structure of full-length M1, and how it oligomerizes to mediate the assembly of virions, is unknown.

Effect of proteolytic processing at two distinct sites on shape and aggregation of an anchorless fusion protein of human respiratory syncytial virus and fate of the intervening segment.

We have examined the consequences of cleaving the fusion glycoprotein (F) of human respiratory syncytial virus (HRSV) at two distinct furin-recognition sites. Purified anchorless F is a mixture of unaggregated cone-shaped molecules and rosettes of lollipop-shaped spikes. The unaggregated molecules contain a proportion of uncleaved F0 and an intermediate, F(delta1-109), cleaved only at site I, residues 106-109.