Btp protein structure, and sequence alignment indicating TIR domains and position of WxxxE motif. (A) Schematic representation of the Brucella BtpA and BtpB proteins with the position of TIR domain boxes and WxxxE motif indicated. (B) Multiple sequence alignment of Brucella melitensis BtpA (AAL52855.1), Brucella suis BtpB (AAN29664.1), Paracoccus denitrificans PdTir (3H16_D), Salmonella enterica TlpA (WP_000116933.1), Escherichia coli TcpC (ADO30450), Yersinia pestis YpTdp (NP_669733.1), human TLR1 (AAY85643.1), human TLR2 (AGR82491.1), human TLR4 (AAY82267.1), human TLR10 (AAY78485.1), SARM (AAH40429.1), Mal/TIRAP (AF406652_1), TRIF (AAH09860), TRAM (NP_067681), MyD88 (AAB49967.1). The alignment shows the sequence encompassing the TIR domain boxes 1 and 2, and WxxxE motif. The alignment was performed with T-coffee analysis, and edited using Jalview, using the ClustalX colour scheme. Structural features indicated above the sequence alignment according to Kaplan-Türköz . The residues mutated in this study are indicated with red (W213, E217, and G183) and black (I226) dots.