The structure–function relationship analysis of Prismalin‐14 from the prismatic layer of the Japanese pearl oyster, Pinctada fucata
The structure–function relationship analysis of Prismalin‐14 from the prismatic layer of the Japanese pearl oyster, Pinctada fucata
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DOI：
10.1111/j.1742-4658.2007.06036.x
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发表时间：
2007-10
期刊：
影响因子：
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通讯作者：
Michio Suzuki;H. Nagasawa
中科院分区：
文献类型：
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作者：
Michio Suzuki;H. Nagasawa
软体动物的壳是由碳酸钙和有机基质组成的硬组织。有机基质被认为在壳的形成中起重要作用。我们之前已经鉴定了一种名为Prismalin-14的棱柱层特异性蛋白，它由105个氨基酸残基组成，包括四个结构特征区域;一个重复的Pro-Ile-Tyr-Arg序列，一个富含Gly/Tyr的区域和N-和C-末端富含Asp的区域。Prismalin-14在体外显示出对碳酸钙沉淀的抑制活性和钙结合能力。在这项研究中，我们在大肠杆菌表达系统中制备了一些分子种类的重组蛋白，包括Prismalin-14及其截短蛋白，以揭示Prismalin-14的结构-功能关系。结果表明，富含Gly/Tyr的区域负责几丁质结合，并被鉴定为新的几丁质结合序列。另一方面，N-和C-末端富含Asp的区域与体外碳酸钙沉淀的抑制活性相关。免疫组织学观察显示Prismalin-14定位于酸不溶性有机框架，包括几丁质。所有这些结果都有力地表明Prismalin-14是一种框架蛋白，通过使用其酸性和几丁质结合区域介导几丁质和碳酸钙晶体。
The mollusk shell is a hard tissue consisting of calcium carbonate and organic matrices. The organic matrices are considered to play important roles in shell formation. We have previously identified a prismatic layer‐specific protein named Prismalin‐14, which consists of 105 amino acid residues and includes four structurally characteristic regions; a repeated sequence of Pro‐Ile‐Tyr‐Arg, a Gly/Tyr‐rich region and N‐ and C‐terminal Asp‐rich regions. Prismalin‐14 showed an inhibitory activity on calcium carbonate precipitation and a calcium‐binding ability in vitro. In this study, we prepared some molecular species of recombinant proteins including Prismalin‐14 and its truncated proteins in an Escherichia coli expression system to reveal a structure–function relationship of Prismalin‐14. The results showed that the Gly/Tyr‐rich region was responsible for chitin binding and was identified as a novel chitin‐binding sequence. On the other hand, both N‐ and C‐terminal Asp‐rich regions are related to inhibitory activity on calcium carbonate precipitation in vitro. Immunohistological observation revealed that Prismalin‐14 was localized at the acid‐insoluble organic framework including chitin. All these results strongly suggest that Prismalin‐14 is a framework protein that mediates chitin and calcium carbonate crystals by using its acidic and chitin‐binding regions.