(A)-(D) The scattering profiles (A), pair distance distribution functions (PDDFs) (B), dimensionless Kratky plots (C) and Porod-Debye plots (D) of the complete sfRNAs of DENV2 (cyan line), ZIKV (red line) and WNV (blue line). The fine features of P1 in the scattering profiles in (A) arise from helical interstrand pair-distance correlation. The PDDF profiles in (B) were calculated using GNOM (qmax=0.3). The dimensionless Kratky plot and Porod-Debye plot for ZIKV xrRNA1 (red dashed line) were included in (C) and (D) for comparison, indicating that the structures of sfRNAs are more extended and open than that of ZIKV xrRNA1. 