Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A galactose-binding protein of M(r) = 30,000 previously described in baby hamster kidney cells (Foddy, L., Stamatoglou, S. C., and Hughes, R. C. (1990) J. Cell Sci. 97, 139-148) has been analyzed by the cloning and sequencing of cDNA clones encoding the complete sequence and an amino-terminal fragment. The intact lectin CBP30 contains 245 amino acid residues, including the initiating methionine residue, and is closely homologous to mammalian S-type lectins of similar size characterized in human, rat, and mouse species. The carboxyl-terminal domain contains the carbohydrate binding activity and the amino-terminal domain, which is extremely sensitive to bacterial collagenase, contains a repetitive sequence rich in glycine, tyrosine, and proline. There are 8 repeats in hamster CBP30, as in the human homologue, compared with about 10 in rat and mouse and > 10 in dog homologues. This repeat sequence is also sensitive to the tissue metalloproteinases, gelatinase B and matrilysin, but, unlike the bacterial collagenase, the mammalian enzymes also cause extensive degradation of the carbohydrate binding carboxyl domain. Physical measurements using CD and tryptophan fluorescence spectroscopy indicate that the two domains of CBP30 are structurally, as well as functionally, distinct and independent. Cross-linking studies indicate that the amino-terminal lectin fragment can efficiently self-assemble into oligomeric species, and less efficient but significant aggregation of the intact lectin is also shown. Domain-specific antibodies to hamster CBP30 have been prepared and used to show that only the full-length, undegraded form of CBP30 is present in whole cell lysates.
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PMID:Structure of baby hamster kidney carbohydrate-binding protein CBP30, an S-type animal lectin. 802 86

The bactericidal activity of mouse alpha-defensins (cryptdins) requires proteolytic activation of inactive precursors by matrix metalloproteinase-7 (matrilysin, EC, MMP-7(a)). To investigate mechanisms of cryptdin-4 (Crp4) peptide interactions with membrane bilayers and to determine whether MMP-7-mediated proteolysis activates the membrane disruptive activity of Crp4, associations of Crp4 and melittin with biomimetic lipid/polydiacetylene chromatic vesicles were characterized. The peptides differ in their sensitivity to vesicle lipid composition and their depth of bilayer penetration. Crp4 undergoes strong interfacial binding onto lipid bilayers with disruption of the bilayer head group region, unlike melittin, which inserts more deeply into the hydrophobic core of the bilayer. Colorimetric and tryptophan fluorescence studies showed that Crp4 insertion is favored by negatively charged phospholipids and that zwitterionic and Escherichia coli phospholipids promote stronger interfacial binding; melittin-membrane interactions were independent of either variable. In contrast to the membrane disruptive activity of Crp4, pro-Crp4 did not perturb vesicular membranes, consistent with the lack of bactericidal activity of the precursor, and incubation of Crp4 with prosegment in trans blocked Crp4 and G1W-Crp4 membrane interactions at concentrations that inhibit Crp4 bactericidal activity. CD measurements showed that Crp4 has an expected beta-sheet structure that is not evident in the pro-Crp4 CD trace or when Crp4 is incubated with prosegment, indicating that the beta-sheet signal is attenuated by proregion interactions or possibly disrupted by the prosegment. Collectively, the results suggest that the prosegment inhibits Crp4 bactericidal activity by blocking peptide-mediated perturbation of target cell membranes, a constraint that is relieved when MMP-7 cleaves the prosegment.
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PMID:Interactions of mouse Paneth cell alpha-defensins and alpha-defensin precursors with membranes. Prosegment inhibition of peptide association with biomimetic membranes. 1257 57

Dysregulation of matrix metalloproteinase (MMP) activity is implicated in tissue destruction under inflammatory conditions. An important mechanism controlling enzymatic activity might involve reactive oxygen species generated by phagocytes. Myeloperoxidase, a heme protein secreted by neutrophils, monocytes, and macrophages, uses hydrogen peroxide to generate hypochlorous acid (HOCl). We demonstrate that HOCl inhibits the activity of human matrilysin (MMP-7) in vitro, suggesting that it might limit proteolytic activity during inflammation. When MMP-7 was exposed to HOCl generated by myeloperoxidase, the proteinase lost activity. High performance liquid chromatographic analysis of the tryptic digest of the HOCl-treated proteinase demonstrated the absence of two peptides that were present in the untreated enzyme. Tandem mass spectrometric analysis revealed that both of the lost peptides contained methionine and tryptophan-glycine residues. The methionine residue of one of the peptides had been oxidized to methionine sulfoxide. In contrast, the major product from the other peptide was 4 atomic mass units smaller than its precursor (WG-4). This novel oxidation product was derived though modification of adjacent tryptophan and glycine residues in the catalytic domain of the enzyme. Loss of proteolytic activity was associated with conversion of the precursor peptide to WG-4 but not with methionine oxidation. In contrast, hydrogen peroxide failed to oxidize MMP-7 or to inactivate the enzyme. Thus, HOCl inactivates MMP-7, perhaps by site-specific conversion of tryptophan-glycine to WG-4. This inactivation mechanism is distinct from the well studied mechanisms involving tissue inhibitors of metalloproteinases. Our findings suggest that local pericellular production of HOCl by phagocytes is a physiological mechanism for governing MMP activity during inflammation.
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PMID:Hypochlorous acid generated by myeloperoxidase modifies adjacent tryptophan and glycine residues in the catalytic domain of matrix metalloproteinase-7 (matrilysin): an oxidative mechanism for restraining proteolytic activity during inflammation. 1275 46

Matrix metalloproteinases (MMPs) function in homeostatic and repair processes, but unregulated catalysis by these extracellular proteinases leads to the pathological destruction of tissue proteins. An important mechanism for controlling enzyme activity might involve hypochlorous acid (HOCl), a potent oxidant produced by the myeloperoxidase system of phagocytes. We have shown that inactivation of MMP-7 (matrilysin) by HOCl coincides with the formation of a novel oxidation product, WG-4, through modification of adjacent tryptophan and glycine residues and loss of 4 atomic mass units. Here, we use mass spectrometry, UV/visible spectroscopy, hydrogen-deuterium exchange, and NMR spectroscopy to investigate the formation and structure of WG-4. For the initial step, HOCl chlorinates the indole ring of tryptophan. The resulting 3-chloroindolenine generates a previously unknown cyclic indole-amide species, in which tryptophan cross-links to the main chain nitrogen of the adjacent glycine residue to form an aromatic six-membered ring. WG-4 kinks and stiffens the peptide backbone, which may hinder the interaction of substrate with the catalytic pocket of MMP-7. Our observations indicate that specific structural motifs are important for controlling protein modification by oxidants and suggest that pericellular oxidant production by phagocytes might limit MMP activity during inflammation.
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PMID:Oxidative cross-linking of tryptophan to glycine restrains matrix metalloproteinase activity: specific structural motifs control protein oxidation. 1467 Sep 64

Matrix metalloproteinases (MMPs) play an essential role in normal and pathological extracellular matrix degradation. Deuterium exchange mass spectrometry (DXMS) was used to localize the binding regions of the broad-spectrum MMP inhibitor doxycycline on the active form of matrilysin (residues 95-267) and to assess alterations in structure induced by doxycycline binding. DXMS analyses of inhibitor-bound versus inhibitor-free forms of matrilysin reveal two primary sites of reduced hydrogen/deuterium exchange (residues 145-153; residues 193-204) that flank the structural zinc binding site. Equilibrium dialysis studies of doxycycline-matrilysin binding yielded a K(d) of 73 microM with a binding stoichiometry of 2.3 inhibitor molecules per protein, which compares well with DXMS results that show principal reduction in deuterium exchange at two sites. Lesser changes in deuterium exchange evident at the amino and carboxyl termini are attributed to inhibitor-induced structural fluctuations. Tryptophan fluorescence quenching experiments of matrilysin with potassium iodide suggest changes in conformation induced by doxycycline binding. In the presence of doxycycline, tryptophan quenching is reduced by approximately 17% relative to inhibitor-free matrilysin. Examination of the X-ray crystal structure of matrilysin shows that the doxycycline-binding site at residues 193 to 204 is positioned within the structural metal center of matrilysin, adjacent to the structural zinc atom and near both calcium atoms. These results suggest a mode of matrilysin inhibition by doxycycline that could involve interactions with the structural zinc atom and/or calcium atoms within the structural metal center of the protein.
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PMID:Molecular interactions between matrilysin and the matrix metalloproteinase inhibitor doxycycline investigated by deuterium exchange mass spectrometry. 1566 54

Most studies of protein oxidation have typically focused on the reactivity of single amino acid side chains while ignoring the potential importance of adjacent sequences in directing the reaction pathway. We previously showed that hypochlorous acid (HOCl), a specific product of myeloperoxidase, inactivates matrilysin by modifying adjacent tryptophan and glycine (WG) residues in the catalytic domain. Here, we use model peptides that mimic the region of matrilysin involved in this reaction, VVWGTA, VVWATA, and the library VVWXTA, to determine whether specific sequence motifs are targeted for chlorination or oxygenation by myeloperoxidase. Our results demonstrate that HOCl generated by myeloperoxidase or activated neutrophils converts the peptide VVWGTA to a chlorinated product, WG+32(Cl). Tandem mass spectrometry in concert with high resolution 1H and two-dimensional NMR analysis revealed that the modification required cross-linking of the tryptophan to the amide of glycine followed by chlorination of the indole ring of tryptophan. In contrast, when glycine in the peptide was replaced with alanine, the major products were mono- and dioxygenated tryptophan residues. When the peptide library VVWXTA (where X represents all 20 common amino acids) was exposed to HOCl, only WG produced a high yield of the chloroindolenine derivative. However, when glycine was replaced by other amino acids, oxygenated tryptophan derivatives were the major products. Our observations indicate that WG may represent a specific sequence motif in proteins that is targeted for chlorination by myeloperoxidase.
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PMID:Specific sequence motifs direct the oxygenation and chlorination of tryptophan by myeloperoxidase. 1654 23

Despite evidence that gonadotropins may facilitate peritoneal metastasis of ovarian cancer by increasing cell adhesion, the action and molecular mechanism of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in ovarian cancer invasion is not well characterized. In the present study, we investigated the effects of FSH and LH on the invasive activity and the expression of metastasis-related proteinases in human epithelial ovarian cancer by Western blot, zymography, reverse transcription-PCR (RT-PCR), ELISA, and Boyden chamber assay. Treatment with FSH or LH (10, 100, or 1,000 ng/mL) significantly increased the invasion of ovarian cancer cell lines, including BG-1, CaOV-3, and SKOV-3 cells but not OVCAR-3 cells. In addition, treatment of SKOV-3 cells with FSH or LH (100 or 1,000 ng/mL) enhanced the expression and activation of matrix metalloproteinases (MMP-2 and MMP-9) as shown by RT-PCR, gelatin zymography, and ELISA. Pretreatment with [(2R)-2-(hydroxamido-carbonylmethyl)-4-methylpentanoyl]-l-tryptophan methylamide (10 micromol/L), a total MMP inhibitor, and 3-(4-phenoxyphenylsulfonyl)-propylthiirane (20 micromol/L), a specific gelatinase inhibitor, neutralized the proinvasive effect of gonadotropins in SKOV-3 cells. In addition, the secretion of tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-2) and plasminogen activator inhibitor-1 was significantly decreased by FSH and LH (100 or 1,000 ng/mL). We further showed that gonadotropins induced an increase in SKOV-3 invasiveness via the activation of protein kinase A (PKA) and phosphatidylinositol 3-kinase (PI3K) signaling pathways. Taken together, these results suggest that gonadotropins may contribute to ovarian cancer metastasis via activation of proteolysis and increase in invasion through the PKA and PI3K pathways.
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PMID:Gonadotropins activate proteolysis and increase invasion through protein kinase A and phosphatidylinositol 3-kinase pathways in human epithelial ovarian cancer cells. 1658 20