Matrix Metalloproteinase-10/TIMP-2 Structure and Analyses Define Conserved Core Interactions and Diverse Exosite Interactions in MMP/TIMP Complexes
Matrix Metalloproteinase-10/TIMP-2 Structure and Analyses Define Conserved Core Interactions and Diverse Exosite Interactions in MMP/TIMP Complexes
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DOI：
10.1371/journal.pone.0075836
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发表时间：
2013-09-20
期刊：
影响因子：
3.7
通讯作者：
Radisky, Evette S.
中科院分区：
文献类型：
--
作者：
Batra, Jyotica;Soares, Alexei S.;Radisky, Evette S.
基质金属蛋白酶（MMPs）在脊椎动物组织发育、重塑和修复中起着重要作用。内源性金属蛋白酶组织抑制剂（TIMPs）通过与MMP活性位点紧密结合来调节蛋白水解活性。虽然四种TIMP中的每一种都可以抑制大多数MMP，但结合数据揭示了不同TIMP/MMP对的亲和力的巨大异质性，并且区分较强复合物与较弱复合物的结构特征知之甚少。在这里，我们报告的晶体结构的相对较弱的结合人MMP-10/TIMP-2复合物在2.1埃分辨率。与先前报道的MMP-3/TIMP-1、MT 1-MMP/TIMP-2、MMP-13/TIMP-2和MMP-10/TIMP-1复合物的结构比较，提供了对结合选择性的结构基础的深入了解。我们的分析确定了一组高度保守的接触在MMP/TIMP复合物的心脏，定义了保守的抑制机制，以及第二类不同的外来接触在接口的外围。TIMP N-末端结构域的AB环和TIMP C-末端结构域的接触环形成高度可变的外周接触，其可以被认为是单独的外部位点相互作用。在一些复合物中，这些外位点接触是广泛的，而在其他复合物中，AB环或C-末端结构域接触大大减少，似乎对复合物稳定性贡献不大。我们的数据表明，exosite相互作用可以增强MMP/TIMP的结合，虽然在相对较弱的结合MMP-10/TIMP-2复合物，他们没有很好地优化这样做。高度可变的外位点相互作用的形成可以提供一种通用机制，通过该机制，TIMP被微调以用于生物学中的不同调节作用。
Matrix metalloproteinases (MMPs) play central roles in vertebrate tissue development, remodeling, and repair. The endogenous tissue inhibitors of metalloproteinases (TIMPs) regulate proteolytic activity by binding tightly to the MMP active site. While each of the four TIMPs can inhibit most MMPs, binding data reveal tremendous heterogeneity in affinities of different TIMP/MMP pairs, and the structural features that differentiate stronger from weaker complexes are poorly understood. Here we report the crystal structure of the comparatively weakly bound human MMP-10/TIMP-2 complex at 2.1 angstrom resolution. Comparison with previously reported structures of MMP-3/TIMP-1, MT1-MMP/TIMP-2, MMP-13/TIMP-2, and MMP-10/TIMP-1 complexes offers insights into the structural basis of binding selectivity. Our analyses identify a group of highly conserved contacts at the heart of MMP/TIMP complexes that define the conserved mechanism of inhibition, as well as a second category of diverse adventitious contacts at the periphery of the interfaces. The AB loop of the TIMP N-terminal domain and the contact loops of the TIMP C-terminal domain form highly variable peripheral contacts that can be considered as separate exosite interactions. In some complexes these exosite contacts are extensive, while in other complexes the AB loop or C-terminal domain contacts are greatly reduced and appear to contribute little to complex stability. Our data suggest that exosite interactions can enhance MMP/TIMP binding, although in the relatively weakly bound MMP-10/TIMP-2 complex they are not well optimized to do so. Formation of highly variable exosite interactions may provide a general mechanism by which TIMPs are fine-tuned for distinct regulatory roles in biology.