Muraoka M, Nakazato K, Hayashi T
Department of Life Sciences-Chemistry, Graduate School of Arts and Sciences, The University of Tokoyo.
J Biochem. 1996 Jan;119(1):167-72. doi: 10.1093/oxfordjournals.jbchem.a021204.
Type IV collagen was prepared from bovine lens capsule by acetic acid extraction, followed by purification including DEAE-Sephacel chromatography and dialysis. The type IV collagen solution became viscous and eventually gelated upon dialysis against 2M guanidine-HCl and 10 mM dithiothreitol. Gelation was not observed for heat-denatured type IV collagen, suggesting that collagenous conformation may be required for the gelation. A reducing agent, dithiothreitol, was essential for the gelation of type IV collagen in 2 M guanidine-HCl. An optimal concentration of guanidine-HCl for the gelation lays between 1.5 and 2.5 M: gelation did not occur at 1 M or lower and at 3 M or higher, although the circular dichroism spectrum characteristic of the collagenous triple-helix was not changed in 3 M guanidine-HCl. This suggests that an appropriate change in conformation of the type IV collagen at a region other than the triple-helical region or/and partial dissociation of complexed type IV collagen aggregates may drive intermolecular interactions of the type IV collagen leading to polymerization and eventually to gelation. To our knowledge, this is the first report that the type IV collagen alone has the ability to form a rigid gel. The assembled structure of the type IV collagen in gel form might be related to the skeletal architecture of basement membrane(s).
IV型胶原通过乙酸提取法从牛晶状体囊中制备，随后进行纯化，包括DEAE - 琼脂糖凝胶柱层析和透析。将IV型胶原溶液对2M盐酸胍和10mM二硫苏糖醇进行透析时，溶液变得粘稠并最终凝胶化。热变性的IV型胶原未观察到凝胶化现象，这表明凝胶化可能需要胶原构象。还原剂二硫苏糖醇对于IV型胶原在2M盐酸胍中的凝胶化至关重要。凝胶化的盐酸胍最佳浓度在1.5至2.5M之间：在1M或更低以及3M或更高浓度时不发生凝胶化，尽管在3M盐酸胍中胶原三螺旋的圆二色光谱特征未改变。这表明IV型胶原在三螺旋区域以外的区域构象发生适当变化和/或复合的IV型胶原聚集体部分解离可能会驱动IV型胶原的分子间相互作用，导致聚合并最终凝胶化。据我们所知，这是首次报道单独的IV型胶原具有形成刚性凝胶的能力。凝胶形式的IV型胶原组装结构可能与基底膜的骨架结构有关。
