Fig. 6: The putative RNA-binding cleft within the IN tetramer.
a Atomic model of the IN tetramer, colored by domain. The four CTDs, which are crucial for RNA binding26,28,29, zigzag along the interface of two IN dimers. b The model is colored by the electrostatic charge distribution. The organization of the CTDs provide a highly positively charged surface stretching over 80 Å, which could effectively bind RNA. A ~40 Å central cavity comprised of inner CTD2 and CTD4 is suitably sized to engage both single- and double-stranded RNAs. The putative path of RNA binding to the IN tetramer is shown in orange. c IN mutations previously analyzed in the literature26,27,28 mapped to the positively charged cleft within the IN tetramer. d IN mutations newly tested in this work mapped to the positively charged cleft within the IN tetramer. e SEC profile of WT and mutant IN proteins, showing their multimerization state (T: tetramer, D: dimer, M: monomer). f Quantification of RNA bridging mediated by purified IN proteins using the AlphaScreen-based RNA bridging assay26. Average values are from four independent experiments, with error bars indicating SDs. Statistical significance was determined by the two tailed t-test (ns, p > 0.05; ***p < 0.001; ****p < 0.0001). The exact p values are reported on the figures. Source data are provided as a Source Data file.
