0000000000642633
AUTHOR
Peter Westbroek
Caspartin: thermal stability and occurrence in mollusk calcified tissues.
8 pages; International audience; The fan mussel Pinna nobilis secretes a two-layered shell, the external layer of which is composed of long calcitic prisms. The dissolution of these prisms releases an assemblage of acidic intracrystalline proteins, among which caspartin, an Asp-rich protein (Marin et al., 2005). A polyclonal antibody raised against purified caspartin was used for estimating its thermal stability, and for investigating the presence of cross-reacting proteins in the shell matrices of several mollusks. In the first case, prisms of Pinna nobilis were heated at 100°C, for one to eleven days. The degradation of caspartin was followed on SDS-PAGE and on Western-blot. The experimen…
Caspartin and calprismin, two proteins of the shell calcitic prisms of the Mediterranean fan mussel Pinna nobilis.
We used the combination of preparative electrophoresis and immunological detection to isolate two new proteins from the shell calcitic prisms of Pinna nobilis, the Mediterranean fan mussel. The amino acid composition of these proteins was determined. Both proteins are soluble, intracrystalline, and acidic. The 38-kDa protein is glycosylated; the 17-kDa one is not. Ala, Asx, Thr, and Pro represent the dominant residues of the 38-kDa protein, named calprismin. An N-terminal sequence was obtained from calprismin. This sequence, which comprises a pattern of 4 cysteine residues, is not related to any known protein. The second protein, named caspartin, exhibits an unusual amino acid composition, …