Protein–Ligand Interactions in the STING Binding Site Probed by Rationally Designed Single-Point Mutations: Experiment and Theory

• DOI: 10.1021/acs.biochem.0c00949
• Publication Date: 2021-02-15T17:50:54Z
• Authors: Zdeněk Vavřina; Ondrej Gutten; Miroslav Smola; Martin Zavřel; Zahra Aliakbar Te...; Vilém Charvát; Milan Kožíšek; Evzen Boura; Gabriel Birkuš; Lubomír Rulíšek
• Keywords: Sting

STING protein (stimulator of interferon genes) plays an important role in the innate immune system. A number potent compounds regulating its activity have been reported, mostly derivatives cyclic dinucleotides (CDNs), natural agonists. Here, we aim to provide complementary information large-scale "ligand-profiling" studies by probing importance STING-CDN protein-ligand interactions on side. We examined detail six typical CDNs each complex with 13 rationally devised mutations STING: S162A, S162T, Y167F, G230A, R232K, R232H, A233L, A233I, R238K, T263A, T263S, R293Q, and G230A/R293Q. The switch off various types interactions: π-π stacking, hydrogen bonding, ionic pairing, nonpolar contacts. correlated experimental data obtained differential scanning fluorimetry, X-ray crystallography, isothermal titration calorimetry theoretical calculations. This enabled us a mechanistic interpretation differences binding representative STING. observed that G230A mutation increased thermal stability complex, indicating level ligand binding, whereas R238K Y167F led complete loss stabilization (ligand binding). effects other depended type (CDN) varied, some extent. very good correlation (R2 = 0.6) between affinities interaction energies computed quantum chemical methods explain effect studied evaluate specific quantitatively. Our work may inspire development high-affinity ligands against common haplotypes targeting key (sometimes non-intuitive) interactions.