Liu Sen, Liu Song, Wang Yanlin, Liao Zhaojiang
Institute of Molecular Biology, China Three Gorges University, Yichang 443002, PR China; College of Medical Science, China Three Gorges University, Yichang 443002, PR China.
Institute of Molecular Biology, China Three Gorges University, Yichang 443002, PR China; College of Medical Science, China Three Gorges University, Yichang 443002, PR China.
Mol Immunol. 2014 Nov;62(1):122-8. doi: 10.1016/j.molimm.2014.05.017. Epub 2014 Jun 28.
Tumor necrosis factor-alpha converting enzyme (TACE) is a proteinase that releases over eighty soluble proteins from their membrane-bound forms, and it has long been an intriguing therapeutic target in auto-immune diseases, and recently, in cancers. However, a haunting question is how TACE recognizes its substrates. In this work, we applied computational and experimental methods to study the role of the P2 site and the P2' site of the substrate peptide in the substrate cleavage of TACE. In the computational complex model, the sidechains of these residues do not form key interactions with TACE, but experimentally, the mutations at these two positions largely affect the peptide cleavage efficiency in the enzymatic assay. We then showed that the P2/P2' sites could affect the efficiency of the conformation search for the correct peptide orientation, which in turn affects the substrate cleavage efficiency. Our result provides new information to the better understanding of the enzymatic mechanism of TACE, and could be useful in the design of novel TACE inhibitors.
肿瘤坏死因子-α转化酶（TACE）是一种蛋白酶，可从其膜结合形式释放八十多种可溶性蛋白质，长期以来它一直是自身免疫性疾病中一个引人关注的治疗靶点，最近在癌症治疗中也是如此。然而，一个萦绕心头的问题是TACE如何识别其底物。在这项工作中，我们应用计算和实验方法来研究底物肽的P2位点和P2'位点在TACE底物切割中的作用。在计算复合物模型中，这些残基的侧链不与TACE形成关键相互作用，但在实验中，这两个位置的突变在酶活性测定中很大程度上影响肽的切割效率。然后我们表明，P2/P2'位点会影响正确肽方向构象搜索的效率，进而影响底物切割效率。我们的结果为更好地理解TACE的酶促机制提供了新信息，并且可能有助于新型TACE抑制剂的设计。
