Characterization of the amino-terminal segment in type III procollagen.
Characterization of the amino-terminal segment in type III procollagen.
复制标题
III 型原胶原氨基末端片段的表征。
DOI：
10.1111/j.1432-1033.1976.tb10971.x
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
R. Timpl
中科院分区：
文献类型：
--
作者：
H. Nowack;B. Olsen;R. Timpl
从胎牛皮肤中制备了天然Ⅲ型胶原蛋白和前胶原蛋白。对蝌蚪胶原酶消化产生的裂解产物进行检测表明，Ⅲ型前胶原蛋白的三条pα1(Ⅲ)链通过分子氨基末端和羧基末端部分的二硫键连接在一起。Ⅲ型胶原蛋白仅在分子的羧基末端区域含有链间二硫键。用细菌胶原酶消化前胶原蛋白后，分离出一种氨基末端的三股肽片段。该片段经还原和烷基化后的链组分分子量约为21000。用溴化氰消化前胶原蛋白后，分离出一种相关的三股片段。溴化氰片段的链分子量约为27000。当胶原酶衍生的肽被完全还原和烷基化后，它变得易于被细菌胶原酶进一步消化。这种处理释放出一个约含97个氨基酸残基的片段，其中含有12个半胱氨酸残基，并且具有球状蛋白质典型的氨基酸组成。第二个约含48个氨基酸残基的非螺旋片段含有3个半胱氨酸。后一个片段由与胶原蛋白α1(Ⅲ)链氨基末端区域重叠20个氨基酸的序列形成，并具有α1(Ⅲ)链特有的抗原决定簇。还原所暴露的对胶原酶敏感的区域约含33个氨基酸残基。它作为小肽的混合物被回收。这些结果表明，Ⅲ型前胶原蛋白的氨基末端区域与Ⅰ型前胶原蛋白的同源区域具有相同类型的结构。它由一个球状结构域、一个类胶原结构域和一个非螺旋结构域组成。然而，链间二硫键结合以及非螺旋结构域中半胱氨酸的存在是Ⅲ型前胶原蛋白所特有的。
Native type III collagen and procollagen were prepared from fetal bovine skin. Examination of the cleavage products produced by digestion with tadpole collagenase demonstrated that the three palpha1(III) chains of type III procollagen were linked together by disulfide bonds occurring at both the amino-terminal and carboxy-terminal portions of the molecule. Type III collagen contained interchain disulfide bonds only in the carboxy-terminal region of the molecule. After digestion of procollagen with bacterial collagenase an amino-terminal, triple-stranded peptide fragment was isolated. The reduced and alkylated chain constituents of this fragment had molecular weights of about 21 000. After digestion of procollagen with cyanogen bromide a related triple-stranded fragment was isolated. The chains of the cyanogen bromide fragment had a molecular weight of about 27 000. When the collagenase-derived peptide was fully reduced and alkylated, it became susceptible to further digestion with bacterial collagenase. This treatment released a fragment of about 97 amino acid residues which contained 12 cystein residues and had an amino acid composition typical for globular proteins. A second, non-helical fragment of about 48 amino acid residues contained three cysteines. This latter fragment is formed from sequences that overlap the amino-terminal region in the collagen alpha1(III) chain by 20 amino acids and possesses an antigenic determinant specific for the alpha1(III) chain. The collagenase-sensitive region exposed by reduction comprised about 33 amino acid residues. It was recovered as a mixture of small peptides. These results indicate that the amino-terminal region of type III procollagen has the same type of structure as the homologous region of type I procollagen. It consists of a globular, a collagen-like and a non-helical domain. Interchain disulfide bonding and the occurrence of cysteines in the non-helical domain are, however, unique for type III procollagen.