Figure 1

Spectroscopic analyses of the interaction between the unfused TGBp2 and viral RNA. A. The amino acid sequence of TGBp2. The TGBp2 protein contains an N-terminal tail, a central loop in between the two transmembrane helices and a C-terminal tail as predicted by ExPASy proteomic tools (HMMTOP 2.0). The two transmembrane helices are highlighted by gray box. (•), the positions of basic amino acid residues replaced with Ala. (▼), the positions of Tyr-to-Ala substitutions. B. Effect of viral RNA on the intrinsic tyrosine fluorescence of Triton X-100-solubilized TGBp2. The Triton X-100-solubilized TGBp2 (2 μM or 25.3 μg/ml) were excited with UV in the presence (at a molar ratio of viral RNA to TGBp2 of 0.35:1) or absence of viral RNA before measurement of tyrosine fluorescence. C. Effect of viral RNA concentration on the intrinsic tyrosine fluorescence of Triton X-100-solubilized TGBp2. Samples of viral RNA and TGBp2 were mixed in various molar ratios, excited with UV and measured for tyrosine fluorescence. In both (B) and (C), the tyrosine fluorescence of TGBp2 was measured at 303 nm after excitation with UV at a wavelength of 280 nm.