Extended Data Fig. 6: Structural analysis of the SfSTING cross-filament contacts.
From: Cryo-EM structure of an active bacterial TIR–STING filament complex
a, Diagonal cross-filament contacts. SfSTING filaments are organized along mainly two planes, one separating pseudosymmetric dimer mates and one at the interface between ‘tetrameric’ dimers (left). Diagonal cross-filament interactions are those that cross the ‘tetramer’ and dimer planes. Additional views of TIR to TIR (middle, STINGs removed for clarity) and STING to STING (right, TIRs removed for clarity) contacts not detailed in main text. S42 is on the TIR BB loop and D112 and G113 are on the TIR DD loop. The STING loops containing P276 and S277 do not make direct electrostatic contacts but do make up a nearly continuous surface that effectively links the cross-tetramer plane related mates. b, Hydrophobic STING to STING cross-filament interactions. The non-polar side chain of V280 extends from a mostly polar and unstructured loop into a hydrophobic cavity formed across the filament ‘tetramer’ interface (left). A309 and A310 brace the hydrophobic face of an opposing α-helix from a STING ‘tetramer’ mate (right).
