Characterization of Prismalin-14, a novel matrix protein from the prismatic layer of the Japanese pearl oyster (Pinctada fucata).
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.
Suzuki
Michio
M
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yayoi 1-1-1, Bunkyo, Tokyo 113-8657, Japan.
Murayama
Emi
E
Inoue
Hirotaka
H
Ozaki
Noriaki
N
Tohse
Hidekazu
H
Kogure
Toshihiro
T
Nagasawa
Hiromichi
H
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D002119:Calcium Carbonate / Q000037:antagonists & inhibitors / Q000737:chemistry; D002135:Calcium-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011232:Chemical Precipitation; D003001:Cloning, Molecular / Q000379:methods; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D007564:Japan; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010125:Ostreidae / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development; D012333:RNA, Messenger / Q000235:genetics; D020539:Sequence Analysis, Protein / Q000379:methods
D002135:Calcium-Binding Proteins; D018076:DNA, Complementary; D012333:RNA, Messenger; D002119:Calcium Carbonate; D002118:Calcium