TLR7 interacts with G in the presence of ssRNA. The binding affinities of G, dG, 8-OHG and 8-OHdG for simian TLR7 ectodomain (sTLR7) with or without PolyU were determined by ITC. (A, B and D–F) ITC analysis of guanosine analogs (G, dG, 8-OHG, 8-OHdG), loxoribine and U binding to sTLR7 with (A, D and E) or without (B and F) PolyU. (C) ITC analysis of the binding of G to PolyU. Calculated Kd are also shown. N.D. means ‘not determined’.