Study on microbial proteiolipid involved in haydroxyapatite formation.

微生物蛋白脂参与羟基磷灰石形成的研究。

• 批准号: 11650819
• 负责人: KURODA Akio
• 金额: $ 2.24万
• 依托单位: Hiroshima University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650819/
• 关键词: hydroxyapatite; phosphate; Calcium; polyphosphate; biomineralization; proteolipid; dental calculus; 歯垢; ポリリン酸; サイクロデキストリン; リン酸化

Corynebacterium matruchotii is a microbe isolated from dental calculus and involved in the calculus formation mainly composed of hydroxyapatite. This microbe is very important for analyzing mechanism of the calcification process. We have purified proteolipid capable of binding eight molecules of calcium ion (Ca^<2+>) from chloroform : methanol lipid extracts It is likely that the initial binding of Ca^<2+> with this proteolipid promotes inorganic phosphate association and eventually hydroxyapatite formation. A PCR-amplified DNA fragment encoding this proteolipid gene (cplX) was inserted into a p-BAD plasmid and then introduced into Escherichia coli. The CplX protein was successfully expressed in E.coli, but the recombinant was not calcified. Removal of covalently attached acyl moieties by methanolic KOH decreased its ability to form Ca-phospholipid. To analyze the differences in acylation sites of CplX in C.matruchotii and E.coli would be very important for further study of the calcification process.

马氏棒杆菌是从牙结石中分离出的一种微生物，它参与牙结石的形成，牙结石主要由羟基磷灰石组成。该微生物对分析钙化过程的机理具有重要意义。我们已经从氯仿：甲醇脂质提取物中纯化出能够结合8个钙离子（Ca^2+）分子的蛋白脂质。很可能Ca^2+与这种蛋白脂质的初始结合促进了无机磷酸盐缔合并最终形成羟基磷灰石。将编码该蛋白脂质基因（cplX）的PCR扩增的DNA片段插入p-BAD质粒中，然后导入大肠杆菌。CplX蛋白在大肠杆菌中成功表达，但重组体未钙化。通过甲醇KOH去除共价连接的酰基部分降低其形成Ca-磷脂的能力。分析CplX在马鲁霍衣藻和大肠杆菌中酰化位点的差异，对于进一步研究钙化过程具有重要意义。