On the Binding of Congo Red to Amyloid Fibrils.

Alba Espargaró, Salomé Llabrés, Sven J Saupe, Carles Curutchet, F Javier Luque, Raimon Sabaté

Angewandte Chemie (International ed. in English) 2020 May 18

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Amyloids are characterized by their capacity to bind Congo red (CR), one of the most used amyloid-specific dyes. The structural features of CR binding were unknown for years, mainly because of the lack of amyloid structures solved at high resolution. In the last few years, solid-state NMR spectroscopy enabled the determination of the structural features of amyloids, such as the HET-s prion forming domain (HET-s PFD), which also has recently been used to determine the amyloid-CR interface at atomic resolution. Herein, we combine spectroscopic data with molecular docking, molecular dynamics, and excitonic quantum/molecular mechanics calculations to examine and rationalize CR binding to amyloids. In contrast to a previous assumption on the binding mode, our results suggest that CR binding to the HET-s PFD involves a cooperative process entailing the formation of a complex with 1:1 stoichiometry. This provides a molecular basis to explain the bathochromic shift in the maximal absorbance wavelength when CR is bound to amyloids. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Alba Espargaró, Salomé Llabrés, Sven J Saupe, Carles Curutchet, F Javier Luque, Raimon Sabaté. On the Binding of Congo Red to Amyloid Fibrils. Angewandte Chemie (International ed. in English). 2020 May 18;59(21):8104-8107