Proteomic characterization of oyster shell organic matrix proteins

Oysters are economically (aquaculture) and ecologically important bivalves, with a calcareous shell that offers mechanical strength and protects them from predators. The shell composition is a blend of inorganic crystals and shell proteins that form an organic matrix which encloses and protects the soft inner tissue of the oyster. It has been found that the mechanical properties of shells of different oyster species vary. The objective of the present study was to compare the composition of shell matrix proteins of two phylogenetically related species: the Hong Kong oyster (C rassostrea hongkongensis ) and the Portuguese oyster (C rassostrea angulata ) which differ in their shell hardness and mechanical properties. Hong Kong oyster shells are comparatively stronger than Portuguese oysters. In the present study, modern proteomics and bioinformatics tools have been used to understand the nature of the Organic Matrix Proteins (OMP) and the possible mechanism involved in the variations observed in the mechanical properties of these two species of oyster shells. After visualizing proteins on SDSPAGE (1DE) and twodimensional electrophoresis (2DE) gels, the protein spots and their intensities were compared using PDQuest software and fourteen proteins of C . hongkongensis were found to be significantly different (student’s ttest; p