Hemocyanin Subunits of a Whipscorpion, Typopeltis crucifer, and a Primitive Spider, Heptathela kimurai: Orthologous Hemocyanin Subunits in Arachnids

Abstract

The presence of monomer and dimer subunits was revealed, by means of native polyacryl-amide gel electrophoresis (PAGE), in examined arachnid hemocyanins. We determined the N-terminal amino acid sequences of nine monomer subunits prepared from hemolymph of a whipscorpion, Typopeltis crucifer, and a primitive spider, Heptathela kimurai, and two constituent monomers of a dimer subunit from the whipscorpion. Based on a comparison of the sequences, we confirmed that the orthologous hemocyanin subunits are shared between the whipscorpion and the scorpion, Liocheles australasiae, between the primitive spider and the scorpion, and among the whipscorpion, the scorpion, and mygalomorph spiders. This study is the first to demonstrate the presence of orthologus hemocyanin subunits in different orders. Furthermore, it is evident that one of the constituent monomers of the hemocyanin dimer from the whipscorpion is orthologous to the constituent monomers (the group G subunits) of the hemocyanin dimers in mygalomorph spiders and to the subunit LA8 (a constituent monomer of a dimer subunit) of the scorpion, suggesting that these constituent monomers of arachnid hemocyanin dimers originated from a common ancestral gene which existed in a common ancestor of these arachnids.