(A) The overall topologies of the TLR8s are remarkably similar, with LRRs superimposing relatively well in most cases apart from the undefined region (LRR14-15). (a) The structural comparison of the human TLR8 with mouse, rat, bovine, and porcine, (d) mouse TLR8 with rat, bovine, and porcine, (c) rat TLR8 with bovine and porcine, (d) bovine TLR8 with porcine. The human, mouse, rat, bovine, and porcine TLR8 are colored in red, cyan, gray, green, and yellow, respectively. (B) Superimposition of the undefined region (LRR14-15) of hTLR8 with other species shows significant differences. (a) All species undefined regions are shown in alpha-carbon trace, (b) side view of the structural differences in the undefined regions are circled, (c) superimposition of the undefined regions shows non-rodent (mouse and rat) that lacks a coil region are circled.