Identification of a Binding Site for ASF/SF2 on an RNA Fragment Derived from the Hepatitis delta Virus Genome
Figure 3
Identification of a binding site for His-ASF/SF2 on R199G RNA.
(A) Representation of the RNA fragments used in comparison to R199G. The proposed His-ASF/SF2 binding site is indicated by the tick bar. (B) Binding affinities of His-ASF/SF2 to the R199G truncation mutants (R177G, R161G, R156G, and R47G), a unit-length HDV genomic RNA (Genomic HDV RNA) and a genomic HDV RNA without the R199G region (Genomic HDV RNA ΔR199G; positions 55 to 1540). (C) Binding affinities of His-ASF/SF2 to various R177G derivatives mutated at the proposed ASF/SF2 binding site. The box in R177ΔASF represents the deletion, and inverted fonts indicate mutations. As in Figure 2, excitation was performed at 280 nm, and emission was monitored at 340 nm. The curves were fitted using non-linear regression to a one-site binding model, and appKD(s) were calculated. Negative symbols indicate that the data could not be fitted to a one-site binding curve equation, consequently no appKD could be calculated. Parentheses for the appKD of R177Gm2fp indicate that this mutant baldy fits to a one-site binding curve equation and no saturation of the complex could be achieved.