Reddy G K, Gunwar S, Kalluri R, Hudson B G, Noelken M E
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66160-7421.
Biochim Biophys Acta. 1993 Jul 11;1157(3):241-51. doi: 10.1016/0304-4165(93)90106-i.
To determine the chain composition of type IV collagen of bovine thoracic aorta, we analyzed collagenase-solubilized carboxyl-terminal noncollagenous (NC1)-domains by high-pressure liquid chromatography, two-dimensional electrophoresis, immunoblotting and enzyme-linked immunoassay. In addition to the classical alpha 1- and alpha 2-chains, we found small amounts of the recently discovered alpha 3-, alpha 4- and alpha 5-chains. The alpha 3- and alpha 4-chains were, collectively, 7-13% of the total, and the alpha 5-chain was present in a low amount. Seventy-nine percent of the NC1-domains were dimerized. Immunolocalization studies on sections of aorta showed that the alpha 3- and alpha 5-chains were present, along with alpha 1- and alpha 2-chains, in the subendothelium and media. In capillaries of the media, the alpha 3-chain was found at relatively high levels and was co-localized with alpha 1- and alpha 2-chains. Digestion of aorta with Pseudomonas aeruginosa elastase yielded soluble multimolecular assemblies of type IV collagen. Electron microscopy results provided a direct demonstration of the supramolecular structure, in which the collagen molecules were tetramerized at the amino-terminal end and dimerized at the carboxyl-terminal end.
为了确定牛胸主动脉IV型胶原蛋白的链组成，我们通过高压液相色谱、二维电泳、免疫印迹和酶联免疫测定法分析了胶原酶溶解的羧基末端非胶原蛋白（NC1）结构域。除了经典的α1链和α2链外，我们还发现了少量最近发现的α3链、α4链和α5链。α3链和α4链合计占总量的7%-13%，α5链含量较低。79%的NC1结构域发生了二聚化。对主动脉切片的免疫定位研究表明，α3链和α5链与α1链和α2链一起存在于内皮下和中膜。在中膜的毛细血管中，发现α3链水平相对较高，并且与α1链和α2链共定位。用铜绿假单胞菌弹性蛋白酶消化主动脉可产生IV型胶原蛋白的可溶性多分子聚集体。电子显微镜结果直接证明了超分子结构，其中胶原分子在氨基末端四聚化，在羧基末端二聚化。
