Multiple sequence alignment of TrpA sequences. Ssolfa_i2_o2C, Aperni_i2_o2C, and Ptorri_i2_o2C represent TrpA sequences from i2_o2 species possessing both an operon-based and a non operon-based trpB2. Tacido_s2E represents a species having exclusively an operon-based trpB2. Ecoli_s1B and Tmarit_i1_o2B represent bacterial TrpA proteins. Mstadt_s1E is from a species possessing exclusively an operon-based trpB1 gene, Mmazei_i1_o2E, Afulgi_i1_o2E and Pfurio_i1_o2E are TrpA sequences from i1_o2 species possessing an operon-based trpB1 and a non operon-based trpB2 gene. Presumably, these TrpA1 proteins interact with a protein of type TrpB1. Below the alignment, the 2D-structure of TrpA of P. furiosus (Pfurio_i1_o2E), and residues involved in protein interaction with its TrpB1 (I) are given. The line named Jpred lists a 2D-prediction of Ssolfa_i2_o2C generated by using the Jpred server . Residues printed in bold are conserved; black residues are strictly, grey residues are less strictly conserved. Active site residues are plotted in italics. These data were deduced from the PDBsum pages  and the PISA server  of the EBI. Residues printed in boxes were predicted by SDPpred  as being specific for the two TrpA species.