FIGURE 3.

Amino acid sequences of kinin precursors from eight tick species. (A) Amino acid sequences were manually curated after mining the available transcriptomes on NCBI. The number of kinin paracopies in each precursor are denoted in the parentheses. The gaps within the protein are denoted with “….” The signal peptides predicted by SignalP 5.0 were underlined. The predicted cleavage sites are in bold, and potential bioactive kinins containing the kinin C-terminal motif, FX₁X₂WG-amide, are highlighted with gray color. The sequence of kinin precursor from Ixodes scapularis was curated based on the putative kinin gene in the genome scaffold (DS680282), while the additional N- and C- terminal sequences were deduced from sequences of three transcripts (Supplementary Figure S3). The number 1 to the left of the Amblyomma sculptum sequence points to an unusual cleavage site (K) or a potential sequencing error at this site (K followed by G) (in black square frame). The version numbers are listed on the top of each sequence (accession numbers are identical except do not contain the 0.1 at the end). (B) Sequence logos of the kinins from eight tick species. The logos were created by WebLogo (Crooks et al., 2004) using the amino acid sequences from each tick kinin precursor between predicted cleavage sites (highlighted in panel A). The overall height of each letter stack indicates the sequence conservation at that position (measured in bits), whereas the height of amino acid symbols within the stack reflects the relative frequency of the corresponding residue at that position. On the X axis, the numbers refer to the amino acid position within the alignment, which was anchored to the conserved C-terminal amidated-glycine residue, similarly as shown in the DINeR database (Yeoh et al., 2017). Toward the N-terminus, logos begin at the position within the alignment where bits are above 0 value. Polar amino acids containing an amide group (Q, N) are in purple, other polar amino acids (G, S, T, Y, C) are in green, basic (K, R, H) are in blue, acidic (D, E) in red and hydrophobic (A, V, L, I, P, W, F, M) amino acids are in black. The dashed-line indicates the bit value of the amino acid residue at the first variable position (X₁) of the kinin C-terminal pentapeptide motif (FX₁X₂WGamide).