Fig. 3: Mutation of Y109 within the RNA-interaction surface diminishes RNA-binding.
a Alignment of NTD sequences from Alpha- and Betacoronaviruses, highlighting conserved residues of the RNA-binding interface (blue) and the triplet residues forming a core network (green for Betacoronaviruses, orange for the hydrophobic core in Alphacoronavirus). Sequences are taken from Uniprot81 entries Q6Q1R8 (HCoV-NL63), P15130 (HCoV-229E), K9N4V7 (MERS-CoV), P33469 (HCoV-OC43), Q5MQC6 (HCoV-HKU1), P59595 (SARS-CoV) and P0DTC9 (SARS-CoV-2), respectively. b Electrostatic surface potential of the WT. Y109–involved in RNA-binding–is located in the β-sheet core as visualized by the cartoon representation on the right. c Comparison of MST-derived KD values for the two RNA-binding deficient mutants R107A and Y109A when titrated with viral Ext RNA (3’-Cy5 labeled). The transition point (50% bound) at the KD of WT is indicated by dotted lines (see also source data). Data are presented as mean values +/− SD from three biological replicates (N = 3), each measured in duplicate. d Zoom-in on the site of mutation in our crystal structure of Y109A. The zoom-in area was set to include regions of significant CSDs from Supplementary Fig. 2b.
