FIG. 1.

INM-SM cassettes used for cross-linking experiments. The N-terminal amino acids of each ORF encoding an ODV envelope protein and containing the features of the INM-SM sequence are shown. The characterized INM-SM sequence derived from E66 is shown for reference (highlighted). Each N-terminal sequence was fused to the same cassette as that shown for E66 containing the amino acids GANA as the linker sequence, followed by a T7 epitope, a lysine-free sequence, and a C-terminal His₇ tag. The hydrophobic sequences are highlighted in yellow, and the associated positively charged amino acids are shown in light red. The positively charged amino acid(s) mutated to lysine to serve as bait for the BS³ cross-linking reagent is noted above the sequence in dark red. All of the resultant fusion proteins have molecular masses of 15 to 18 kDa.