Immunological Correspondence Between Arthropod Hemocyanin Subunits. II. Xiphosuran(Limulus)and Spider(Eurypelma, Cupiennius)Hemocyanin

Publisher Website
Google Scholar
Abstract
The hemocyanins of the horeshoe crab Limulus polyphemus (48-mer), the tarantula Eurypelma californicum (24-mer), and the hexamer) were dissociated into subunits, the subunits isolated and studied by 2-dimensional immunoelectrophoresis for interspecific cross-reactivities. Among the subunits a to g of Eurypelma on the one side, and I to VI of Limulus on the other, a number of cross-reactions were obtained which agree with the topoloic subunit positions in the published models of quaternary structure: a = II, b-c = V-VI, d = IV, e = I, f = IIIB, g = IIIa (IIa). However, cross-reactivity was only strong in the following combinations: a/II, d/IV, b-c/V-VI (the monomers of the 2 heterodimers could not be correlated individually). A rather weak cross-reaction was obtained in the case of e/I and g/IIIa (IIa); a cross-reaction between and IIIb was almost undetectable. On the hand, f/IV clearly cross-reacted, and so did e/IIIa (IIa), which apparently is not in agreement with the 2 models of quaternary structure. These unexpected relationships, however, indicate the possible phylogeny of the subunits. Antiserum against Cupiennius hemocyanin precipitated subunit f of Eurypelma and subunit IV of Limulus and, moreover, revealed common antigen determinants present on these subunits. Denaturation of hemocyaniun subunits of the 3 species with 8 M urea yielded a completely different immunological behavior in that in all intra- and interspecific combinations the reaction of immunological identity was obtained. The published models of quaternary structure and a possible subunit phylogeny of cheliceratan hemocyanins is discussed in view of the present results and the results of a previous paper.

This publication has 18 references indexed in Scilit: