ADAMTS13蛋白C-末端结构调节其酶活性的研究

目的 初步研究并探讨ADAMTS13蛋白C-末端结构域变化在调节其酶活性方面的作用.方法 将人全长野生型及缺失C-末端TSP8和CUB结构域的截短型重组ADAMTS13基因转染Hela细胞并稳定表达.分别在静态尿素变性条件及蜗旋装置提供的高剪切力条件下观察这两种ADAMTS13蛋白酶切血管性血友病因子(vWF)的差异,同时利用Western blot技术及残余胶原结合实验对结果进行检测,另外利用ELISA法直接检测这两种ADAMTS13蛋白静态条件下结合vWF的能力.结果 在Hela细胞真核表达载体表达并纯化了全长野生型及缺失C-末端TSP8和CUB结构域的截短型ADAMTS13蛋白,分别利用鼠抗His-Tag单抗(抗载短型ADAMS113单)及兔抗人ADAMTS13多抗Western blot法鉴定了其特异性.静态尿素变性条件下,截短型ADAMTS13蛋白酶活性显著高于野生型,且静态条件下在结合vWF的能力方面,截短型也显著高于野生型;但在高剪切力作用下,只有全长野生型ADAMTS13可以对vWF进行剪切.结论 ADAMTS13蛋白C-末端TSP8和CUB结构域在不同条件下可以调节ADAMTS13蛋白结合vWF的能力,从而调节其酶活性的发挥,ADAMTS13蛋白C-末端在高剪切力作用条件下对ADAMTS13酶活性的发挥至关重要.

Research on the C-terminal domain of ADAMTS13 regulates its cleaving activity

Objective To study the influence of C-terminal domain of ADAMTS13 on its cleaving activity. Methods The full-length wild-type (WT) and C-terminal domain truncated type (TT, TSP8 +CUB domains were deleted) of human ADAMTS13 recombinant protein were transfected into and permanent expressed on Hela cells. Western blot and R-CBA were used to directly detect the activities of the two recombinant proteins under the static and stressed condition respectively. ELISA was used to compare the binding abilities of the two proteins by coating with vWF. Results The recombinant proteins were identified by Western blot with anti-his-tag or anti-ADAMTS13 antibodies. With pretreatment of 1.5 M urea, the enzyme activity of TT was significantly higher than that of WT, and so did in binding ability with vWF While, only WT could cleave vWF under high stress. Conclusion The distal carboxyl-terminal TSP8 together with CUB domains of ADAMTS13 may affect the enzyme activity by regulating the binding of ADAMTS13 to vWF in different conditions, and they are very important for the enzyme activity under high stress force condition.