Fig. 2. Multiple alignment of the toll/interleukin receptor (TIR) domain of TLR4. The number suffix indicates the corresponding TLR of that species. The alpha helices and beta sheets are indicated beneath the alignment. TM, transmembrane region; HR, hydrophobic region; asterisk, site of LPS^d mutation; 1, residues important in the BB protein interaction site; and 2, residues important in the DD loop protein interaction site. Sequences used in the alignment are detailed in Table 2.