Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Covalent single-chain dimers of the chemokine interleukin-8 (IL-8) have been designed to mimic the dimeric form of IL-8 in solution and facilitate the production of heterodimer variants of IL-8. Physical studies indicated that use of a simple peptide linker to join two subunits, while allowing receptor binding and activation, led to self-association of the tethered dimers. However, addition of a single disulfide crosslink between the tethered subunits prevented this multimer from forming, yielding a species of dimer molecular weight. Crosslinked single-chain dimers bind to both IL-8 neutrophil receptors CXCR1 and CXCR2 as well as to DARC, as does a double disulfide-linked dimer with no peptide linker. In addition, neutrophil response to these dimers as measured by chemotaxis or beta-glucuronidase release is similar to that elicited by wild-type IL-8, providing evidence that the dissociation of the dimeric species is not required for these biologically relevant activities. Finally, through construction of single-chain heterodimer mutants, we show that only the first subunit's ELR motif is the single-chain variants.
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PMID:IL-8 single-chain homodimers and heterodimers: interactions with chemokine receptors CXCR1, CXCR2, and DARC. 907 Apr 43

In studies aimed at developing a high affinity IL-8 antagonist, our first objective was to generate a high-affinity IL-8 analogue. We targeted amino acids within the receptor-binding domain and found that IL-8((3-73))K11R induced significantly more neutrophil beta-glucuronidase release than either IL-8 or the alternate analogues and, in chemotaxis assays, induced 2-3-fold greater neutrophil responses than IL-8. Furthermore, in competitive radio- or biotinylated-ligand binding assays, IL-8((3-73))K11R was more effective than IL-8, IL-8((3-73)), or its T12S, H13F, and K11R/T12S/H13F analogues in blocking IL-8 binding to neutrophils; 1.8 pmol IL-8((3-73))K11R inhibited by 50% the binding of approximately 20 pmol (125)I-IL-8 to neutrophils. Both IL-8 (a CXCR1/CXCR2 ligand) and the CXCR2-specific ligand GROalpha differentially inhibited binding of (125)I-IL-8((3-73))K11R to neutrophils, albeit weakly, suggesting that IL-8((3-73))K11R is a high affinity ligand for both the CXCR1 and CXCR2. Thus IL-8((3-73))K11R is an excellent candidate for further studies aimed at generating a high affinity IL-8 antagonist.
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PMID:Il-8((3-73))K11R is a high affinity agonist of the neutrophil CXCR1 and CXCR2. 1151 Nov 1

We recently reported that CXCL8((3-73))K11R is a high affinity agonist of neutrophil activation and chemotactic responses. In this report we employed CXCL8((3-73))K11R as a template to generate CXCL8/IL-8 analogues with antagonist activities, using site-directed mutagenesis to introduce conservative amino acid substitutions into the first turn within the molecule's beta-pleated sheet region (G31P, P32G) and, in association with these, into the putative receptor-recognition site (T12S, H13F, F17S). We then examined their impact on the analogues' biological activities and found that a G31P substitution rendered CXCL8((3-73))K11R a high affinity antagonist of CXCL8/IL-8. The ranking (in the order of decreasing CXCL8/IL-8 antagonist activities) of the CXCL8((3-73))K11R analogues we generated was, G31P>T12S/G31P>H13F/G31P>T12S/H13F/G31P>>P32G approximately T12S/P32G approximately H13F/P32G>T12S/H13F/P32G; CXCL8((3-73))K11R/F17S did not inhibit CXCL8/IL-8-dependent responses. CXCL8((3-73))K11R/G31P had no discernible agonist (beta-glucuronidase release, chemotactic) activity, but at 12.5 ng/ml it bound to purified neutrophils more avidly than did 1.25 microg/ml CXCL8/IL-8. Furthermore, CXCL8((3-73))K11R/G31P competitively antagonized the binding of CXCR1- and CXCR2-specific antibodies to these receptors. Taken together, these data thus provide further impetus to the study of the potential efficacy of CXCL8((3-73))K11R/G31P as a broad-spectrum antagonist of the ELR-CXC chemokines in experimental and clinical settings.
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PMID:CXCL8((3-73))K11R/G31P antagonizes ligand binding to the neutrophil CXCR1 and CXCR2 receptors and cellular responses to CXCL8/IL-8. 1205 49