In Situ D-periodic Molecular Structure of Type II Collagen
In Situ D-periodic Molecular Structure of Type II Collagen
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DOI：
10.1074/jbc.m109.060400
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发表时间：
2010-03-05
影响因子：
4.8
通讯作者：
Orgel, Joseph P. R. O.
中科院分区：
文献类型：
--
作者：
Antipova, Olga;Orgel, Joseph P. R. O.
胶原蛋白是多细胞动物细胞外基质的重要成分。纤维状 II 型胶原蛋白是关节软骨和其他软骨样组织（例如脊索）的最重要成分。其原位大分子和堆积结构尚未完全表征，但对这些属性的了解可能有助于揭示组织组装和降解的机制（如骨关节炎和类风湿关节炎）。在一些组织中，例如七鳃鳗脊索，胶原纤维组织是天然结晶的，可以通过 X 射线衍射进行研究。我们使用天然和衍生脊索组织样本的衍射数据，通过多重同形替换来解决 II 型胶原的轴向 D 周期结构。电子密度图和重原子数据揭示了天然组织中 II 型胶原蛋白的非螺旋端肽的构象和整体 D 周期结构，这些数据得到了结构预测和透射电子显微镜的进一步支持。这些结果有助于解释观察到的 I 型胶原和 II 型胶原纤维结构的差异，并表明 II 型胶原交联组织，这对于纤维形成至关重要。透射电子显微镜数据显示七鳃鳗和哺乳动物胶原原纤维之间存在密切关系，尽管各自较大规模的组织结构不同。
Collagens are essential components of extracellular matrices in multicellular animals. Fibrillar type II collagen is the most prominent component of articular cartilage and other cartilage-like tissues such as notochord. Its in situ macromolecular and packing structures have not been fully characterized, but an understanding of these attributes may help reveal mechanisms of tissue assembly and degradation (as in osteo- and rheumatoid arthritis). In some tissues such as lamprey notochord, the collagen fibrillar organization is naturally crystalline and may be studied by x-ray diffraction. We used diffraction data from native and derivative notochord tissue samples to solve the axial, D-periodic structure of type II collagen via multiple isomorphous replacement. The electron density maps and heavy atom data revealed the conformation of the nonhelical telopeptides and the overall D-periodic structure of collagen type II in native tissues, data that were further supported by structure prediction and transmission electron microscopy. These results help to explain the observed differences in collagen type I and type II fibrillar architecture and indicate the collagen type II cross-link organization, which is crucial for fibrillogenesis. Transmission electron microscopy data show the close relationship between lamprey and mammalian collagen fibrils, even though the respective larger scale tissue architecture differs.