Entropy Increases from Different Sources Support the High-affinity Binding of the N-terminal Inhibitory Domains of Tissue Inhibitors of Metalloproteinases to the Catalytic Domains of Matrix Metalloproteinases-1 and -3

Ying Wu,Shuo Wei,Steven R Van Doren,Keith Brew

doi:10.1074/jbc.m111.222307

Abstract

The avid binding of tissue inhibitors of metalloproteinases (TIMPs) to matrix metalloproteinases (MMPs) is crucial for the regulation of pericellular and extracellular proteolysis. The interactions of the catalytic domain (cd) of MMP-1 with the inhibitory domains of TIMP-1 and TIMP-2 (N-TIMPs) and MMP-3cd with N-TIMP-2 have been characterized by isothermal titration calorimetry and compared with published data for the N-TIMP-1/MMP-3cd interaction. All interactions are largely driven by increases in entropy but there are significant differences in the profiles for the interactions of both N-TIMPs with MMP-1cd as compared with MMP-3cd; the enthalpy change ranges from small for MMP-1cd to highly unfavorable for MMP-3cd (-0.1 ± 0.7 versus 6.0 ± 0.5 kcal mol(-1)). The heat capacity change (ΔC(p)) of binding to MMP-1cd (temperature dependence of ΔH) is large and negative (-210 ± 20 cal K(-1) mol(-1)), indicating a large hydrophobic contribution, whereas the ΔC(p) values for the binding to MMP-3cd are much smaller (-53 ± 3 cal K(-1) mol(-1)), and some of the entropy increase may arise from increased conformational entropy. Apart from differences in ionization effects, it appears that the properties of the MMP may have a predominant influence in the thermodynamic profiles for these N-TIMP/MMP interactions.

Highlights

The matrix metalloproteinases (MMPs)3 catalyze the turnover of components of the extracellular matrix and have important roles in tissue remodeling, wound healing, embryo implantation, cell migration, and shedding of cell surface proteins [1, 2]
We report here an investigation by ITC of the interactions of N-terminal domains of tissue inhibitors of metalloproteinases (TIMPs) (N-TIMPs)-1 with the catalytic domain of MMP-1 (MMP-1cd) and N-TIMP-2 with the catalytic domains of both MMP-1 and MMP-3
To determine the contribution to ⌬Hobs of enthalpy changes arising from protonation or deprotonation on complex formation, the enthalpies of binding (⌬Hobs) for the interactions of N-TIMP-2 with both MMPs were measured at 291 K in buffers of different enthalpies of ionization, Pipes, Hepes, Bes, and Aces (Table 1 and Fig. 3)

Summary

Introduction

The matrix metalloproteinases (MMPs) catalyze the turnover of components of the extracellular matrix and have important roles in tissue remodeling, wound healing, embryo implantation, cell migration, and shedding of cell surface proteins [1, 2]. In the crystal structures of the MMP-31⁄7TIMP-1, MMP-11⁄7NTIMP-1, MT1-MMP1⁄7TIMP-2, and MMP-131⁄7TIMP-2 complexes (4 –7), most of the MMP interaction surface is located within the N-domains of the TIMPs; as shown, the N-terminal region (residues 1–5) inserts into the active site of the MMP, whereas the ␣-amino group together with the carbonyl oxygen of Cys coordinate the catalytic zinc (4 –7). In the all inhibitory TIMP1⁄7MMP complexes, the side chain of residue 2 of the TIMP (Ser or Thr in vertebrate TIMPs) sits over the mouth of the key S1Ј subsite of the MMP active site (4 –7), and substitution by glycine results in large loss of affinity for most MMPs [9, 12] Both the Ala extension and Thr to Gly mutation in N-TIMP-3 have little effect on the inhibition of ADAM-17, ADAMTS-4, or ADAMTS-5 [9, 13]. The truncated N-terminal domains of TIMPs (N-TIMPs) and isolated MMP catalytic domains (MMPcd) have been extensively used in studies of the interactions between TIMPs and MMPs [12,13,14,15,16,17,18,19] and the majority of the intermolecular interactions in structurally characterized inhibitory TIMP1⁄7MMP complexes involve residues in these domains

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Conclusion