Characterization of the N-terminal segment used by the barley yellow dwarf virus movement protein to promote interaction with the nuclear membrane of host plant cells

The barley yellow dwarf virus movement protein (BYDV-MP) requires its N-terminal sequence to promote the transport of viral RNA into the nuclear compartment of host plant cells. Here, graphical analysis predicts that this sequence would form a membrane interactive amphiphilic α-helix. Confirming this prediction, NT1, a peptide homologue of the BYDV-MP N-terminal sequence, was found to be α-helical (65%) in the presence of vesicles mimics of the nuclear membrane. The peptide increased the fluidity of these nuclear membrane mimics (rise in wavenumber of circa 0.5–1.0 cm−1) and induced surface pressure changes of 2 mN m−1 in lipid monolayers with corresponding compositions. Taken with isotherm analysis these results suggest that BYDV-MP forms an N-terminal amphiphilic α-helix, which partitions into the nuclear membrane primarily through thermodynamically stable associations with the membrane lipid headgroup region. We speculate that these associations may play a role in targeting of the nuclear membrane by BYDM-MP.