Jellyfish Mesogloea Collagen

The mesogloea collagen of a primitive animal, the jellyfish Stomolophus nomurai, belonging to the class Scyphozoa in the Coelenterata, was studied with respect to its chain structure. Most of the mesogloea collagen was solubilized by limited digestion with pepsin and isolated by selective precipitation at 0.9 M NaCl in 0.5 M acetic acid. Upon denaturation, the pepsinsolubilized collagen produced three distinct a chains, al, a2, and a3, in comparable amounts which were separable by CM-cellulose chromatography. The nonidentity of these a chains was confirmed by amino acid and carbohydrate analyses and peptide mapping. Furthermore, the introduction of intramolecular crosslinks into native molecules by formaldehyde yielded a large proportion of yIz3 chain with chain structure ala2a3, as judged by chromatographic behavior and peptide maps. We concluded that mesogloea collagen is comprised of ala2a3 heterotrimers and is chemically like vertebrate Type V collagen. On the other hand, sea anemone mesogloea collagen from the class Anthozoa was previously reported to comprise homotrimers (Katzman, R. L., and Kang, A. H. (1972) J. Biol. Chem. 247,5486-5489). On the basis of these findings, we assume that ala2a3 heterotrimers arose in evolution with the divergence of Scyphozoa and Anthozoa.