ABSTRACT
The conformational analysis of glycosidases affords a route to their specific inhibition through transition-state mimicry. Inspired by the rapid reaction rates of cyclophellitol and cyclophellitol aziridine-both covalent retaining ß-glucosidase inhibitors-we postulated that the corresponding carba "cyclopropyl" analogue would be a potent retaining ß-glucosidase inhibitor for those enzymes reacting through the 4H3 transition-state conformation. Ab initio metadynamics simulations of the conformational free energy landscape for the cyclopropyl inhibitors show a strong bias for the 4H3 conformation, and carba-cyclophellitol, with an N-(4-azidobutyl)carboxamide moiety, proved to be a potent inhibitor (Ki = 8.2 nM) of the Thermotoga maritima TmGH1 ß-glucosidase. 3-D structural analysis and comparison with unreacted epoxides show that this compound indeed binds in the 4H3 conformation, suggesting that conformational strain induced through a cyclopropyl unit may add to the armory of tight-binding inhibitor designs.
Subject(s)
Cyclohexanols/pharmacology , Glycoside Hydrolase Inhibitors/pharmacology , alpha-Glucosidases/metabolism , Cyclohexanols/chemistry , Glycoside Hydrolase Inhibitors/chemistry , Models, Molecular , Molecular Structure , Quantum Theory , Thermotoga maritima/enzymologyABSTRACT
Glucosylceramide metabolism and the enzymes involved have attracted significant interest in medicinal chemistry, because aberrations in the levels of glycolipids that are derived from glucosylceramide are causative in a range of human diseases including lysosomal storage disorders, typeâ 2 diabetes, and neurodegenerative diseases. Selective modulation of one of the glycoprocessing enzymes involved in glucosylceramide metabolism-glucosylceramide synthase (GCS), acid glucosylceramidase (GBA1), or neutral glucosylceramidase (GBA2)-is therefore an attractive research objective. In this study we took two established GCS inhibitors, one based on deoxynojirimycin and the other a ceramide analogue, and merged characteristic features to obtain hybrid compounds. The resulting 39-compound library does not contain new GCS inhibitors; however, a potent (200â nm) GBA1 inhibitor was identified that has little activity toward GBA2 and might therefore serve as a lead for further biomedical development as a selective GBA1 modulator.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Glucosyltransferases/antagonists & inhibitors , 1-Deoxynojirimycin/chemical synthesis , 1-Deoxynojirimycin/chemistry , 1-Deoxynojirimycin/metabolism , Ceramides/chemical synthesis , Ceramides/chemistry , Ceramides/metabolism , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/metabolism , Glucosamine/analogs & derivatives , Glucosamine/chemical synthesis , Glucosamine/chemistry , Glucosamine/metabolism , Glucosyltransferases/metabolism , Humans , Inhibitory Concentration 50 , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Protein Binding , Structure-Activity RelationshipABSTRACT
BACKGROUND: Listeria monocytogenes meningitis is the third most common cause of bacterial meningitis and is associated with high rates of mortality and unfavorable outcome. METHODS: We analyzed 101 cytokines, chemokines and complement factors in CSF of adult patients with Listeria meningitis included in a prospective cohort study and compared these biomarkers between Listeria meningitis patients and negative controls, and between Listeria meningitis patients with a favorable and an unfavorable outcome. RESULTS: CSF was available from 26 of 62 (42%) Listeria meningitis patients and 19 negative controls. Fifteen (58%) Listeria meningitis patients had an unfavorable outcome. In Listeria meningitis CSF levels of 51 biomarkers were significantly elevated compared to negative controls after Bonferroni correction. The 11 most significantly elevated (P < .01) biomarkers of unfavorable outcome in Listeria meningitis were markers of T-cell activation (sIL-2Rα, sCD40L and IL-1), interferon-related (IFN-α2, IL-18, CX3CL1, CCL20), markers of complement activation (C3a), and endothelial growth factor related (VEGF, CXCL7). CONCLUSIONS: Our data suggest that T-cell activation, complement activation, interferon- and endothelial growth factor production are important in the immune response to Listeria meningitis, and thereby influence outcome. GENERAL SIGNIFICANCE: Our study provides target pathways for further studies in the pathophysiology of Listeria meningitis.