Structure of the aphid RlpA. (A) ClustalX alignment of amino acid sequences of RlpAs. Residues conserved in all lineages, four lineages, and three lineages are shaded black, dark gray, and light gray, respectively. Residues contributing to the domain structures are boxed. A residue that is different between type I and type II of A. pisum RlpA is denoted with an asterisk. (B) Domain structure of the aphid RlpA protein and structures of the corresponding mRNA and genomic DNA. For reference, the domain structure of E. coli RlpA is also shown. (C) Alignment of ICK motifs of the aphid RlpA with those of three antimicrobial peptides of the harlequin beetle, Acrocinus longimanus. Asterisks indicate the residues conserved in all the sequences. The grey background indicates conserved cysteines. The percentage of identity and E-value of bl2seq performed between each sequence and the ICK motif-1 (the one on the N- terminal side) of the pea aphid RlpA are shown on the right. Dashes (-) indicate alignment gaps. Dots (.) represent residues identical to those of the pea aphid RlpA.