Coutinho M, Aulak K S, Davis A E
Division of Nephrology, Children's Hospital Research Foundation, Cincinnati, OH 45229-3039.
J Immunol. 1994 Oct 15;153(8):3648-54.
To analyze the role of the heavily glycosylated amino-terminal domain of C1 inhibitor in protease inhibitory activity, two truncated C1 inhibitor molecules were constructed. The abilities of the recombinant truncated inhibitors to complex with target proteases were compared with that of the wild-type recombinant protein. One recombinant truncated molecule consisted of amino acid residues 76 to 478 (C-serp(76)) and the other of residues 98 to 478 (C-serp(98)). The recombinant proteins were each expressed in similar quantities. The thermal denaturation profiles of the two truncated proteins were similar to that of the wild-type protein. Identical binding of C1s, C1r, kallikrein, and beta factor XIIa was observed with the three molecules. Furthermore, the truncated molecules also effectively inhibited C1 activity in hemolytic assays. These studies therefore clearly demonstrate that the amino-terminal domain of C1 inhibitor does not influence complex formation with target proteases.
为分析C1抑制剂高度糖基化的氨基末端结构域在蛋白酶抑制活性中的作用，构建了两种截短的C1抑制剂分子。将重组截短抑制剂与靶蛋白酶形成复合物的能力与野生型重组蛋白进行了比较。一种重组截短分子由氨基酸残基76至478组成（C-serp(76)），另一种由残基98至478组成（C-serp(98)）。两种重组蛋白的表达量相似。两种截短蛋白的热变性曲线与野生型蛋白相似。观察到三种分子对C1s、C1r、激肽释放酶和β-因子XIIa的结合相同。此外，截短分子在溶血试验中也有效抑制了C1活性。因此，这些研究清楚地表明，C1抑制剂的氨基末端结构域不影响与靶蛋白酶形成复合物。
