Pronounced diversity in electronic and chemical properties between the catalytic zinc sites of tumor necrosis factor-α-converting enzyme and matrix metalloproteinases despite their high structural similarity
Pronounced diversity in electronic and chemical properties between the catalytic zinc sites of tumor necrosis factor-α-converting enzyme and matrix metalloproteinases despite their high structural similarity
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DOI：
10.1074/jbc.m401310200
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发表时间：
2004-07-23
影响因子：
4.8
通讯作者：
Sagi, I
中科院分区：
文献类型：
--
作者：
Solomon, A;Rosenblum, G;Sagi, I
金属蛋白酶肿瘤坏死因子-α-转换酶（TACE）参与多个关键生理和病理过程的调节。因此，为了研究 TACE 的生理作用以及治疗目的，迫切需要有效的、选择性的合成抑制剂。由于 TACE 的活性位点与解整合素 (ADAM) 和基质金属蛋白酶 (MMP) 等其他相关锌内肽酶的活性位点之间高度结构相似，因此设计此类定制抑制剂并非易事。为了获得对这个问题的新见解，我们使用选择性 MMP 抑制剂作为探针来检查抑制时 TACE 活性位点发生的结构和动力学效应。具体来说，我们使用基于选择性 MMP 机制的抑制剂 SB-3CT 来表征 TACE 和 MMP-2 活性位点内催化锌离子之间的精细结构和电子差异。我们发现 SB-3CT 直接结合 TACE 的金属离子，正如之前用 MMP-2 观察到的那样。然而，与MMP-2相比，SB-3CT与TACE催化锌离子的结合模式在Zn-S(SB-3CT)键距长度和催化锌离子的总有效电荷方面有所不同。此外，SB-3CT 通过诱导结构的显着构象变化，以非竞争性方式抑制 TACE。对于 MMP-2，SB-3CT 表现为竞争性抑制剂，未观察到显着的构象变化。对这些酶的催化锌离子周围的第二壳氨基酸的检查表明，TACE 的活性位点比 MMP-2 和其他 MMP 的活性位点更具极性。基于这些结果，我们提出，尽管 TACE 和 MMP-2 之间看似具有很高的结构相似性，但这些酶在其活性位点内的电子和化学性质方面存在显着差异。
The metalloproteinase tumor necrosis factor-alpha-converting enzyme ( TACE) is involved in the regulation of several key physiological and pathological processes. Therefore, potent and selective synthetic inhibitors are highly sought for the study of the physiological roles of TACE as well as for therapeutic purposes. Because of the high structural similarities between the active site of TACE and those of other related zinc endopeptidases such as disintegrin (ADAMs) and matrix metalloproteinases ( MMPs), the design of such tailor-made inhibitors is not trivial. To obtain new insights into this problem, we have used a selective MMP inhibitor as a probe to examine the structural and kinetic effects occurring at the active site of TACE upon inhibition. Specifically, we used the selective MMP mechanism-based inhibitor SB-3CT to characterize the fine structural and electronic differences between the catalytic zinc ions within the active sites of TACE and MMP-2. We show that SB-3CT directly binds the metal ion of TACE as observed before with MMP-2. However, in contrast to MMP-2, the binding mode of SB-3CT to the catalytic zinc ion of TACE is different in the length of the Zn-S(SB-3CT) bond distance and the total effective charge of the catalytic zinc ion. In addition, SB-3CT inhibits TACE in a non-competitive fashion by inducing significant conformational changes in the structure. For MMP-2, SB-3CT behaved as a competitive inhibitor and no significant conformational changes were observed. An examination of the second shell amino acids surrounding the catalytic zinc ion of these enzymes indicated that the active site of TACE is more polar than that of MMP-2 and of other MMPs. On the basis of these results, we propose that although there is a seemingly high structural similarity between TACE and MMP-2, these enzymes are significantly diverse in the electronic and chemical properties within their active sites.