Interactions in the TLR2/6-MyD88 tetramer interface region.

The TIR domains of TLR2, 6 and MyD88 are represented as ribbon models. TLR2 and 6 receptor chains A and B are shown in sky blue and light green colors, respectively. MyD88 (C and D) adapter chains are shown in gold color. Major structural motifs that contribute to the TLR6-MyD88 interface include BB-loop and αC-helix of TLR6 and CD loop, βD and αE-helix of MyD88. At the TLR2-MyD88 interface, the important structural motifs include BB-loop and αC-helix of TLR2 and beginning of BB-loop and αB-helix of MyD88. The interacting residues in the tetramer residual interface region are highlighted in boxes. Side chains of the amino acids contributing to hydrogen bond formation are represented as a stick model with the residue names and numbers shown next to them. Black dotted lines represent the hydrogen bonds.