Smad 7 N端结构域的生物信息学及生物化学特性

Bioinformatics and Biochemical Characterization of Human Smad 7 N-terminal Domain

Smad 7蛋白是一种对TGF-β信号通路产生负调节作用的重要蛋白。对Smad 7的氨基酸序列进行生物信息学分析,根据分析结果构建一系列删除不同氨基酸片段的重组蛋白,最后对这些蛋白进行生物化学特性分析。结果显示:Smad 7 N端前20个左右的氨基酸影响蛋白质的可溶性,它的删除还会造成蛋白质聚集,因此推测这些氨基酸残基在蛋白质折叠过程中有重要作用。同时Smad 7 N端存在一个较大的不易折叠的Loop结构,对蛋白质高级结构的形成起到负面作用。Loop的存在导致蛋白质易降解、不均一,而删除这段结构可以提高蛋白质的稳定性。本研究为Smad 7 N端结构域蛋白的结构生物学研究打下了坚实基础。

Smad 7 is an important negative regulator of the TGF-β signaling pathway.In this study,we analyzed Smad 7 NTD（N-Terminal Domain） sequence by the bioinformatics approaches.In addition,we established different constructs of Smad 7 NTD with various deletions of residues according to the bioinformatics analysis results,and investigated the biochemical properties of Smad 7 NTD deletion constructs.The results revealed that the N-terminal 20 residues of Smad 7 was critical for its solubility,suggesting that it played an important role in the folding of Smad 7 NTD.Furthermore,our bioinformatics and biochemical results indicated that there was a large intrinsically unfolded Loop in Smad 7 NTD,which made this structure unstable and susceptible for proteolytic degradation.Removal of this Loop remarkably improved the stability and monomericity of Smad 7 NTD domain protein,which would be suitable for future crystallographic studies.