FIG 2.

The SP24 family of virion membrane proteins of insect viruses. The boundaries of the predicted TM segments are approximative. We assumed that the topology of SP24 was conserved in all of the viruses, but in chroparaviruses (first two sequences), TM segment 2 is less hydrophobic and thus may be simply membrane associated, which would generate a different overall topology. The N-and C-terminal regions have no detectable sequence similarity and are presented only for information; whether they are homologous is unknown. Predicted N-glycosylation sites are indicated for N- and C-terminal regions only. Actual N-glycosylation can occur only if these regions are on the outside the virion, which we cannot reliably predict (see text).