Elastin Degradation by Cathepsin V Requires Two Exosites
Elastin Degradation by Cathepsin V Requires Two Exosites
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DOI：
10.1074/jbc.m113.510008
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发表时间：
2013-11-29
影响因子：
4.8
通讯作者：
Broemme, Dieter
中科院分区：
文献类型：
--
作者：
Du, Xin;Chen, Nelson L. H.;Broemme, Dieter
背景：弹性蛋白降解是皮肤、肺和血管系统的各种病理学中的关键事件。结果：组织蛋白酶V降解弹性蛋白需要两个外切位点。结论：组织蛋白酶外切位点支持对不溶性弹性蛋白的识别和结合。重要性：外切位点可能是选择性抑制组织蛋白酶弹性蛋白酶活性的新靶点。组织蛋白酶V是一种高效的弹性蛋白酶，参与生理和病理性细胞外基质降解。然而，其作用机制仍然难以捉摸。尽管人组织蛋白酶V表现出有效的弹性蛋白分解活性，但共享78%氨基酸序列的结构同源的组织蛋白酶L对不溶性弹性蛋白仅具有最小的蛋白水解活性。这表明存在在弹性蛋白溶解中起重要作用的不同结构域。在这项研究中，共产生了11个嵌合体的组织蛋白酶V和L，以确定弹性蛋白结合结构域的组织蛋白酶V。这些嵌合体的评价发现两个外切位点有助于弹性蛋白酶的活性组织蛋白酶V是远离活性裂缝的蛋白酶，并位于表面环区域。用来自组织蛋白酶L的类似残基替换外切位点1或2分别导致弹性蛋白溶解活性损失75%和43%。两个外切位点的替换产生了类似于组织蛋白酶L的非弹性蛋白酶变体。这些外切位点的鉴定可能有助于设计抑制剂，其仅影响半胱氨酸组织蛋白酶的弹性蛋白分解活性而不干扰其他生理蛋白酶功能。
Background: Elastin degradation is a key event in various pathologies of the skin, lung, and the vascular system. Results: Elastin degradation by cathepsin V requires two exosites. Conclusion: Cathepsin exosites support the recognition of and binding to insoluble elastin. Significance: Exosites may represent novel target sites for the selective inhibition of the elastase activity of cathepsins.Cathepsin V is a highly effective elastase and has been implicated in physiological and pathological extracellular matrix degradation. However, its mechanism of action remains elusive. Whereas human cathepsin V exhibits a potent elastolytic activity, the structurally homologous cathepsin L, which shares a 78% amino acid sequence, has only a minimal proteolytic activity toward insoluble elastin. This suggests that there are distinct structural domains that play an important role in elastinolysis. In this study, a total of 11 chimeras of cathepsins V and L were generated to identify elastin-binding domains in cathepsin V. Evaluation of these chimeras revealed two exosites contributing to the elastolytic activity of cathepsin V that are distant from the active cleft of the protease and are located in surface loop regions. Replacement of exosite 1 or 2 with analogous residues from cathepsin L led to a 75 and 43% loss in the elastolytic activity, respectively. Replacement of both exosites yielded a non-elastase variant similar to that of cathepsin L. Identification of these exosites may contribute to the design of inhibitors that will only affect the elastolytic activity of cysteine cathepsins without interfering with other physiological protease functions.