6533b85efe1ef96bd12bf998

RESEARCH PRODUCT

Calcification in the Shell of the Freshwater Bivalve Unio pictorum.

subject

description

8 pages; International audience; The scope of the present study is to elucidate the primary structure of the shell proteins of the mollusk Unio pictorum. This freshwater bivalve exhibits an aragonitic shell with nacro-prismatic microstructures. The acetic acid-soluble matrix of the nacreous layer has been extracted, and analyzed on standard polyacrylamide gel under denaturing conditions. Five main proteins can be observed. Their respective apparent molecular weight is 95, 50, 29, 14 and 10 kDa. The three high molecular weight bands are acidic, glycosylated and bind calcium in vitro. These proteins are purified by preparative SDSPAGE. In addition, these fractions are tested to check their ability to modify the shape of CaCO3 crystals. The biochemical properties of these proteins can be compared to that of other proteins of nacreous mollusks, such as Pinctada sp., Pinna nobilis, Haliotis sp. and Turbo marmoratus.