Electron microscopic studies on collagen fibrillogenesis.

1. 我们之前发现胶原分子在pH为4.5时特异性地形成4d交错线性聚合物，这被认为是体外胶原纤维形成的第一个中间体。在本研究中，我们证实了在生理条件下，4d -交错聚集体（含有不同程度的聚合）被纳入原生型d -周期原纤维。我们打算通过凝胶过滤分离不同聚合度的低聚物，并确定每种低聚物在胶原纤维形成中的作用。试验尚未成功。研究了胶原自组装第一步分子（二聚体）结合形式的电镜鉴定条件，并优化了个别方法。我们注意到I型胶原分子束（SLS）的负染色带状模式与分子上疏水氨基酸的分布直接相关。与I型和II型胶原蛋白的相关性得到证实。在pH值4.5.4时，胶原蛋白分子的非螺旋部分（端肽）参与了4d交错结合。体外纤维形成早期的电镜检查显示，除了细丝外，还存在d周期原纤维（初步观察）。

1. We previously found that collagen molecules associate at pH 4.5 to specifically form 4D-staggered linear polymers, which are assumed to be the first intermediates in in vitro collagen fibrillogenesis. In this study, we confirmed that the 4D-staggered aggregates (containing various degrees of polymerization) are incorporated into native-type D-periodic fibrils under the physiological conditions. We intended to isolate the oligomers of the different polymericity by gel filtration and to assign the role of each oligomer in collagen fibrillogenesis. The trials were not yet successful.2. Conditions for electron microscopic identification of the association form of the molecules (dimer) at the first step of collagen self-assembly were investigated and individual methods were optimized. We noticed the direct correlation between negatively stained banding patern of type I collagen molecular bundle (SLS) and the distribution of hydrophobic amino acids along the molecule. The correlation was confirmed with type I and type II collagens.3. Non-helical parts of the collagen molecule (telopeptide) were revealed to be involved in the 4D-staggered association at pH 4.5.4. Electron microscopic examination of the sample taken at an early stage of the in vitro fibrillogenesis showed the existance of D-periodic fibrils in addition to thin filaments (preliminaly obsevation).