Characterization of Prismalin-14, a novel matrix protein from the prismatic layer of the Japanese pearl oyster (Pinctada fucata)

• Published in: Biochemical journal Vol. 382; no. Pt 1; pp. 205 - 213
• Main Authors: Suzuki, Michio, Murayama, Emi, Inoue, Hirotaka, Ozaki, Noriaki, Tohse, Hidekazu, Kogure, Toshihiro, Nagasawa, Hiromichi
• Format: Journal Article
• Language: English
• Published: England Portland Press Ltd 15.08.2004
• Subjects: Amino Acid Sequence; Animals; Calcium - antagonists & inhibitors; Calcium - metabolism; Calcium Carbonate - antagonists & inhibitors; Calcium Carbonate - chemistry; Calcium-Binding Proteins - chemistry; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - isolation & purification; Calcium-Binding Proteins - metabolism; Chemical Precipitation; Cloning, Molecular - methods; DNA, Complementary - genetics; Gene Expression Regulation - genetics; Japan; Marine; Molecular Sequence Data; Organ Specificity - genetics; Ostreidae - chemistry; Ostreidae - genetics; Ostreidae - growth & development; RNA, Messenger - genetics; Sequence Analysis, Protein - methods; Japan
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/bj20040319

The mollusc shell is a hard tissue consisting of calcium carbonate and organic matrices. The organic matrices are believed to play important roles in shell formation. In the present study, we extracted and purified a novel matrix protein, named Prismalin-14, from the acid-insoluble fraction of the prismatic layer of the shell of the Japanese pearl oyster (Pinctada fucata), and determined its whole amino acid sequence by a combination of amino acid sequence analysis and MS analysis of the intact protein and its enzymic digests. Prismalin-14 consisted of 105 amino acid residues, including PIYR repeats, a Gly/Tyr-rich region and N- and C-terminal Asp-rich regions. Prismalin-14 showed inhibitory activity on calcium carbonate precipitation and calcium-binding activity in vitro. The scanning electron microscopy images revealed that Prismalin-14 affected the crystallization of calcium carbonate in vitro. A cDNA encoding Prismalin-14 was cloned and its expression was analysed. The amino acid sequence deduced from the nucleotide sequence of Prismalin-14 cDNA was identical with that determined by peptide sequencing. Northern-blot analysis showed that a Prismalin-14 mRNA was expressed only at the mantle edge. In situ hybridization demonstrated that a Prismalin-14 mRNA was expressed strongly in the inner side of the outer fold of the mantle. These results suggest that Prismalin-14 is a framework protein that plays an important role in the regulation of calcification of the prismatic layer of the shell.