- Substrate specificity of an actively assembling amyloid catalyst
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In the presence of Zn2+, the catalytic, amyloid-forming peptide Ac-IHIHIQI-NH2, was found to exhibit enhanced selectivity for hydrophobic p-nitrophenyl ester substrates while in the process of self-assembly. As opposed to the substrate p-nitrophenyl acetate, which was more effectively hydrolyzed with Ac-IHIHIQI-NH2 in its fully fibrillar state, the hydrophobic substrate Z-L-Phe-ONp was converted with a second-order rate constant more than 11-times greater when the catalyst was actively assembling. Under such conditions, Z-L-Phe-ONp hydrolysis proceeded at a greater velocity than the more hydrophilic and otherwise more labile ester Boc-L-Asn-ONp. When assembling, the catalyst also showed increased selectivity for the L-enantiomer of Z-Phe-ONp. These findings suggest the occurrence of increased interactions of hydrophobic moieties of the substrate with exposed hydrophobic surfaces of the assembling peptides and present valuable features for future de novo design consideration.
- Heier, Jason L.,Mikolajczak, Dorian J.,B?ttcher, Christoph,Koksch, Beate
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- Comparative metabolomics and structural characterizations illuminate colibactin pathway-dependent small molecules
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The gene cluster responsible for synthesis of the unknown molecule colibactin has been identified in mutualistic and pathogenic Escherichia coli. The pathway endows its producer with a long-term persistence phenotype in the human bowel, a probiotic activity used in the treatment of ulcerative colitis, and a carcinogenic activity under host inflammatory conditions. To date, functional small molecules from this pathway have not been reported. Here we implemented a comparative metabolomics and targeted structural network analyses approach to identify a catalog of small molecules dependent on the colibactin pathway from the meningitis isolate E. coli IHE3034 and the probiotic E. coli Nissle 1917. The structures of 10 pathway-dependent small molecules are proposed based on structural characterizations and network relationships. The network will provide a roadmap for the structural and functional elucidation of a variety of other small molecules encoded by the pathway. From the characterized small molecule set, in vitro bacterial growth inhibitory and mammalian CNS receptor antagonist activities are presented.
- Vizcaino, Maria I.,Engel, Philipp,Trautman, Eric,Crawford, Jason M.
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supporting information
p. 9244 - 9247
(2014/07/21)
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- Amino acid conjugates of lithocholic acid as antagonists of the EphA2 receptor
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The Eph receptor-ephrin system is an emerging target for the development of novel antiangiogenetic agents. We recently identified lithocholic acid (LCA) as a small molecule able to block EphA2-dependent signals in cancer cells, suggesting that its (5β)-cholan-24-oic acid scaffold can be used as a template to design a new generation of improved EphA2 antagonists. Here, we report the design and synthesis of an extended set of LCA derivatives obtained by conjugation of its carboxyl group with different α-amino acids. Structure-activity relationships indicate that the presence of a lipophilic amino acid side chain is fundamental to achieve good potencies. The l-Trp derivative (20, PCM126) was the most potent antagonist of the series disrupting EphA2-ephrinA1 interaction and blocking EphA2 phosphorylation in prostate cancer cells at low μM concentrations, thus being significantly more potent than LCA. Compound 20 is among the most potent small-molecule antagonists of the EphA2 receptor.
- Incerti, Matteo,Tognolini, Massimiliano,Russo, Simonetta,Pala, Daniele,Giorgio, Carmine,Hassan-Mohamed, Iftiin,Noberini, Roberta,Pasquale, Elena B.,Vicini, Paola,Piersanti, Silvia,Rivara, Silvia,Barocelli, Elisabetta,Mor, Marco,Lodola, Alessio
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supporting information
p. 2936 - 2947
(2013/05/22)
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- Kinase inhibitor compounds
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The invention relates to compounds, compositions comprising the compounds, and methods of using the compounds and compound compositions. The compounds, compositions, and methods described herein can be used for the therapeutic modulation of kinase-mediated processes, and treatment of disease and disease symptoms, particularly those mediated by certain kinase enzymes.
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Page/Page column 44
(2009/04/24)
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- KINASE INHIBITOR COMPOUNDS
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The invention relates to compounds, compositions comprising the compounds, and methods of using the compounds and compound compositions. The compounds, compositions, and methods described herein can be used for the therapeutic modulation of kinase-mediated processes, and treatment of disease and disease symptoms, particularly those mediated by certain kinase enzymes.
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Page/Page column 86
(2008/06/13)
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- NEW PENICILLINS FROM ISOPENICILLIN N SYNTHASE.
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The three tripeptides δ-L-α-aminoadipoyl-L-cysteinyl-D-propargylglycine, δ-L-α-aminoadipoyl-L-cysteinyl-D-cyanoalanine and δ-L-α-aminoadipoyl-L-cysteinyl-D--norvaline were synthesised and incubated with the enzyme Isopenicillin N Synthase (IPNS).All incubation mixtures contained biologically active products, and led to the isolation of four new penicillins (β-ethyl, α-acetylenic, α- and β-nitrile) following purification by reverse phase HPLC.The stereochemistries of formation of monosubstituted penicillins with IPNS are rationalised.
- Baldwin, Jack E.,Bradley, Mark,Abbott, Shaun D.,Adlington, Robert M.
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p. 5309 - 5328
(2007/10/02)
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- Enantioselectivity in Chiral Inverted Micelles and Co-surfactant Localization in Microemulsion
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The enantioselectivity observed in a study of the imidazole-catalysed hydrolysis of enantiomeric pairs of three amino acids in chiral reversed micelles proves that the reaction takes place in the micelle membrane.
- Andriamanampisoa, Ramarofidy,Boyer, Bernard,Lamaty, Gerard,Roque, Jean Pierre
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p. 597 - 598
(2007/10/02)
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