Structural studies on human type IV collagen.
Structural studies on human type IV collagen.
复制标题
人类 IV 型胶原蛋白的结构研究。
DOI：
--
复制
发表时间：
1979
影响因子：
4.8
通讯作者：
P. Bornstein
中科院分区：
文献类型：
--
作者：
H. Sage;R. Woodbury;P. Bornstein
IV型胶原是通过在酸性和中性ph下的选择性盐沉淀从人胎盘的有限胃蛋白酶消化中分离出来的。这种天然蛋白对人皮肤胶原酶有抗性，但被大鼠肥大细胞蛋白酶裂解。还原和烷基化后的材料分子筛色谱分离出相对均一的分子量为140000 （140K）和100000 （100K）的组分，第三个分子量为70000的组分在cm -纤维素上进一步分馏为70K-I和7OK-II组分。用溴化氰和肥大细胞蛋白酶消化变性链产生的氨基酸组成和肽图表明，1OOK和7k - 1片段来自较大的140K片段，但更基本的70K-II片段代表不同的序列，最有可能来自相关但不同的胶原链。这些数据与胎盘中存在两种遗传上不同的iv型胶原链一致。抗胃蛋白酶胶原片段含有约三分之一的甘氨酸，按分子筛色谱和丙烯酰胺凝胶电泳标准分子量为140,000，按沉降平衡分子量为145,000，这表明IV型胶原蛋白中存在比I型胶原蛋白a链更长的三螺旋区域，即使考虑到该链中羟基赖氨酸连接的碳水化合物含量。
Type IV collagen was isolated from limited pepsin digests of human placenta by selective salt precipitation at acidic and neutral pH. The native protein was resistant to human skin collagenase but was cleaved by a rat mast cell protease. Molecular sieve chromatography of the reduced and alkylated material separated relatively homogeneous components of molecular weight 140,000 (140K) and 100,000 (100K) and a third component of molecular weight 70,000 which was further fractionated on CM-cellulose into 70K-I and 7OK-II components. Amino acid compositions and peptide maps produced by digestion of the denatured chains with cyanogen bromide and mast cell protease indicated that the 1OOK and 7OK-I fragments were derived from the larger 140K fragment, but that the more basic 70K-II fragment represented a different sequence which was most probably derived from a related but distinct collagen chain. The data are consistent with the presence of two genetically distinct type IV-like collagen chains in placenta. The existence of a pepsin-resistant collagenous fragment that contains approximately one-third glycine and has a molecular weight of 140,000 by the criteria of molecular sieve chromatography and acrylamide gel electrophoresis, and 145,000 by sedimentation equilibrium, argues for the presence of a triple-helical region in type IV collagen that is longer than an a chain of type I collagen, even when the hydroxylysine-linked carbohydrate content of this chain is considered.