Role of RNA Guanine Quadruplexes in Favoring the Dimerization of SARS Unique Domain in Coronaviruses

Cécilia Hognon; Tom Miclot; Cristina Garcia Iriepa; Antonio Francés-Monerris; Stephanie Grandemange; Alessio Terenzi; Marco Marazzi; Giampaolo Barone; Antonio Monari

. CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.07.029447 doi: bioRxiv preprint As previously observed qualitatively, the presence of G4 in the dimeric binding mode induces rigidity in the SUD subunits interface due to the formation of the dimer. This effect can be quantified by analyzing the distribution of the distance of a tweezer in the SUD interface area formed by the residues Ala355 and Arg266, as reported in Figure 4 . Indeed, while in the case of the dimeric-like conformation a peaked distribution centered at relative close distances (6.7 Ã…) is observed, indicating a closed and quite rigid disposition, a much broader and bimodal distribution is found for the monomer-like conformation, presenting, most notably, a secondary maximum at about 11 Ã…, which confirms the partial destabilization of the SUD subdomains interface and the greater flexibility induced by this binding mode. The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.07.029447 doi: bioRxiv preprint