title: Pronounced diversity in electronic and chemical properties between the catalytic zinc sites of tumor necrosis factor-alpha-converting enzyme and matrix metalloproteinases despite their high structural similarity.
abstract: 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.
authors.affiliation: Department of Structural Biology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
authors.forename: Ariel
authors.initials: A
authors.lastname: Solomon
authors.forename: Gabriel
authors.initials: G
authors.lastname: Rosenblum
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Gonzales
authors.forename: Jennifer D
authors.initials: JD
authors.lastname: Leonard
authors.forename: Shahriar
authors.initials: S
authors.lastname: Mobashery
authors.forename: Marcos E
authors.initials: ME
authors.lastname: Milla
authors.forename: Irit
authors.initials: I
authors.lastname: Sagi
mesh_terms: D051722:ADAM Proteins; D000072198:ADAM17 Protein; D020134:Catalytic Domain; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D020778:Matrix Metalloproteinase 2 / Q000737:chemistry* / Q000235:genetics; D061965:Matrix Metalloproteinase Inhibitors; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics; D055672:Static Electricity; D013450:Sulfones / Q000737:chemistry / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015032:Zinc / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D006573:Heterocyclic Compounds, 1-Ring; D061965:Matrix Metalloproteinase Inhibitors; D011994:Recombinant Proteins; C429533:SB 3CT compound; D013450:Sulfones; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D015032:Zinc