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Thermodynamic Origins of Selectivity in the Interactions of N- TIMP Variants and Metalloproteinases Catalytic Domains

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Date Issued:
2016
Summary:
Matrix metalloproteinases (MMPs) constitute the major class of enzymes capable of degrading all protein components of extracellular matrix (ECM) and have important roles in normal physiologic processes of maintaining tissue integrity and remodeling. However, excess MMP activities are associated with many diseases including rheumatoid arthritis and osteoarthritis, cardiomyopathy, and macular degeneration. The activity of MMPs is regulated by their endogenous protein inhibitors, the tissue inhibitors of metalloproteinases (TIMPs) which are avid broad-spectrum inhibitors of numerous human matrixins (MMPs and ADAMs). Uncontrolled matrix degradation occurs when the balance between TIMPs and MMPs is disrupted, resulting in serious diseases such as cancer, arthritis and chronic tissue ulcers. Thus, the engineering of TIMPs to produce highly selective and efficacious inhibitors of individual MMPs may be utilized for future treatment of diseases. Such engineering requires detailed analysis for the structural and biophysical information of MMP-TIMP interaction. Changes in the dynamics of proteins and solvent that accompany their associations with different binding partners, influence the specificity of binding through entropic effects. From the current studies it appears that the interactions of the inhibitory domains of TIMPs-1 and -2 (N-TIMPs) with MT1-MMP are driven by entropy increases that are partitioned between solvent and conformational entropy (ΔSsolv and ΔSconf), and a large conformational entropy penalty is responsible for the weak inhibition of MT1-MMP by NT1.We investigated how mutations that modify N-TIMP selectivity affect the thermodynamics of interactions with MMP1, MMP3 and MT1-MMP. The weak inhibition of MT1-MMP by N-TIMP-1 is enhanced by mutation of threonine 98, on the edge of the binding ridge, to leucine. This mutation increases the large ΔSconf cost for binding to MT1-MMP but this is offset by a greater increase in ΔSsolv. In contrast, this mutation enhances binding to MMP3 by increasing ΔSconf for the interaction. ΔSsolv and ΔSconf show mutual compensation for all interactions, with characteristic ranges for each MMP. Distinct electrostatic and dynamic features of MMPs are key factors in their selective inhibition.
Title: Thermodynamic Origins of Selectivity in the Interactions of N- TIMP Variants and Metalloproteinases Catalytic Domains.
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Name(s): Zou, Haiyin, author
Brew, Keith, Thesis advisor
Florida Atlantic University, Degree grantor
Charles E. Schmidt College of Medicine
Department of Biomedical Science
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Date Created: 2016
Date Issued: 2016
Publisher: Florida Atlantic University
Place of Publication: Boca Raton, Fla.
Physical Form: application/pdf
Extent: 133 p.
Language(s): English
Summary: Matrix metalloproteinases (MMPs) constitute the major class of enzymes capable of degrading all protein components of extracellular matrix (ECM) and have important roles in normal physiologic processes of maintaining tissue integrity and remodeling. However, excess MMP activities are associated with many diseases including rheumatoid arthritis and osteoarthritis, cardiomyopathy, and macular degeneration. The activity of MMPs is regulated by their endogenous protein inhibitors, the tissue inhibitors of metalloproteinases (TIMPs) which are avid broad-spectrum inhibitors of numerous human matrixins (MMPs and ADAMs). Uncontrolled matrix degradation occurs when the balance between TIMPs and MMPs is disrupted, resulting in serious diseases such as cancer, arthritis and chronic tissue ulcers. Thus, the engineering of TIMPs to produce highly selective and efficacious inhibitors of individual MMPs may be utilized for future treatment of diseases. Such engineering requires detailed analysis for the structural and biophysical information of MMP-TIMP interaction. Changes in the dynamics of proteins and solvent that accompany their associations with different binding partners, influence the specificity of binding through entropic effects. From the current studies it appears that the interactions of the inhibitory domains of TIMPs-1 and -2 (N-TIMPs) with MT1-MMP are driven by entropy increases that are partitioned between solvent and conformational entropy (ΔSsolv and ΔSconf), and a large conformational entropy penalty is responsible for the weak inhibition of MT1-MMP by NT1.We investigated how mutations that modify N-TIMP selectivity affect the thermodynamics of interactions with MMP1, MMP3 and MT1-MMP. The weak inhibition of MT1-MMP by N-TIMP-1 is enhanced by mutation of threonine 98, on the edge of the binding ridge, to leucine. This mutation increases the large ΔSconf cost for binding to MT1-MMP but this is offset by a greater increase in ΔSsolv. In contrast, this mutation enhances binding to MMP3 by increasing ΔSconf for the interaction. ΔSsolv and ΔSconf show mutual compensation for all interactions, with characteristic ranges for each MMP. Distinct electrostatic and dynamic features of MMPs are key factors in their selective inhibition.
Identifier: FA00004643 (IID)
Degree granted: Dissertation (Ph.D.)--Florida Atlantic University, 2016.
Collection: FAU Electronic Theses and Dissertations Collection
Note(s): Includes bibliography.
Subject(s): Metalloproteinases -- Inhibitors.
Proteolytic enzymes.
Extracellular matrix proteins.
Apoptosis.
Held by: Florida Atlantic University Libraries
Sublocation: Digital Library
Persistent Link to This Record: http://purl.flvc.org/fau/fd/FA00004643
Use and Reproduction: Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
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Host Institution: FAU
Is Part of Series: Florida Atlantic University Digital Library Collections.