A cementum protein 1‐derived peptide (CEMP1‐p1) consisting of 20 amino acids from the CEMP1's N‐terminus region: MGTSSTDSQQAGHRRCSTSN, and its role on the mineralization process in a cell‐free system, was characterized. CEMP1‐p1's physicochemical properties, crystal formation, and hydroxyapatite (HA) nucleation assays were performed. Crystals induced by CEMP1‐p1 were analyzed by scanning electron microscopy, Fourier‐transform infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR), X‐ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and atomic force microscopy. The results indicate that CEMP1‐p1 lacks secondary structure, forms nanospheres that organize into three‐dimensional structures, possesses affinity to HA, and induces its nucleation. CEMP1‐p1 promotes the formation of spherical structures composed by densely packed prism‐like crystals, which revealed a Ca/P ratio of 1.56, corresponding to HA. FTIR‐ATR showed predominant spectrum peaks that correspond and are characteristic of HA and octacalcium phosphate (OCP). Analysis by XRD indicates that the crystals show planes with a preferential crystalline orientation for HA and for OCP. HRTEM showed interplanar distances that correspond to crystalline planes of HA and OCP. Crystals are composed by superimposed lamellae, which exhibit epitaxial growth, and each layer of the crystals is structured by nanocrystals. This study reveals that CEMP1‐p1 regulates HA crystal formation, somehow mimicking the in vivo process of mineralized tissues bioformation.

中文翻译：

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骨水泥蛋白1衍生肽（CEMP 1-p1）在体外调节羟基磷灰石晶体的形成。

牙骨质蛋白1衍生肽（CEMP1-p1），由CEMP1 N端的20个氨基酸组成区域：MGTSSTDSQQAGHRRCSTSN，及其在无细胞系统中矿化过程中的作用。进行了CEMP1-p1的理化特性，晶体形成和羟基磷灰石（HA）成核分析。通过扫描电子显微镜，傅立叶变换红外光谱-衰减全反射率（FTIR-ATR），X射线衍射（XRD），高分辨率透射电子显微镜（HRTEM）和原子力显微镜对CEMP1-p1诱导的晶体进行了分析。结果表明，CEMP1-p1缺乏二级结构，形成组织成三维结构的纳米球，对HA具有亲和力，并诱导其成核。CEMP1-p1促进了由密集堆积的棱柱状晶体组成的球形结构的形成，Ca / P比为1.56，与HA相对应。FTIR-ATR显示的主要光谱峰与HA和磷酸八钙（OCP）相对应并具有特征。通过XRD分析表明，晶体显示出对于HA和OCP具有优先晶体取向的平面。HRTEM显示出与HA和OCP的晶面相对应的晶面距离。晶体由叠加的薄片组成，这些薄片表现出外延生长，并且晶体的每一层都由纳米晶体构成。这项研究表明CEMP1-p1调节HA晶体的形成，以某种方式模仿了矿化组织生物形成的体内过程。HRTEM显示出与HA和OCP的晶面相对应的晶面距离。晶体由叠加的薄片组成，这些薄片表现出外延生长，并且晶体的每一层都由纳米晶体构成。这项研究表明CEMP1-p1调节HA晶体的形成，以某种方式模仿了矿化组织生物形成的体内过程。HRTEM显示出与HA和OCP的晶面相对应的晶面距离。晶体由叠加的薄片组成，这些薄片表现出外延生长，并且晶体的每一层都由纳米晶体构成。这项研究表明，CEMP1-p1调节HA晶体的形成，以某种方式模仿了矿化组织生物形成的体内过程。