Structure–activity relationship of ipglycermide binding to phosphoglycerate mutases

Catalysis of human phosphoglycerate mutase is dependent on a 2,3-bisphosphoglycerate cofactor (dPGM), whereas the nonhomologous isozyme in many parasitic species is cofactor independent (iPGM). This mechanistic and phylogenetic diversity offers an opportunity for selective pharmacologic targeting of glycolysis in disease-causing organisms. We previously discovered ipglycermide, a potent inhibitor of iPGM, from a large combinatorial cyclic peptide library. To fully delineate the ipglycermide pharmacophore, herein we construct a detailed structure–activity relationship using 280 substituted ipglycermide analogs. Binding affinities of these analogs to immobilized Caenorhabditis elegans iPGM, measured as fold enrichment relative to the index residue by deep sequencing of an mRNA display library, illuminated the significance of each amino acid to the pharmacophore. Using cocrystal structures and binding kinetics, we show that the high affinity of ipglycermide for iPGM orthologs, from Brugia malayi, Onchocerca volvulus, Dirofilaria immitis, and Escherichia coli, is achieved by a codependence between (1) the off-rate mediated by the macrocycle Cys14 thiolate coordination to an active-site Zn2+ in the iPGM phosphatase domain and (2) shape complementarity surrounding the macrocyclic core at the phosphotransferase–phosphatase domain interface. Our results show that the high-affinity binding of ipglycermide to iPGMs freezes these structurally dynamic enzymes into an inactive, stable complex

A target-agnostic screen identifies approved drugs to stabilize the endoplasmic reticulum-resident proteome

Endoplasmic reticulum (ER) dysregulation is associated with pathologies including neurodegenerative, muscular, and diabetic conditions. Depletion of ER calcium can lead to the loss of resident proteins in a process termed exodosis. To identify compounds that attenuate the redistribution of ER proteins under pathological conditions, we performed a quantitative high-throughput screen using the Gaussia luciferase (GLuc)-secreted ER calcium modulated protein (SERCaMP) assay, which monitors secretion of ER-resident proteins triggered by calcium depletion. We identify several clinically used drugs, including bromocriptine, and further characterize them using assays to measure effects on ER calcium, ER stress, and ER exodosis. Bromocriptine elicits protective effects in cell-based models of exodosis as well as in vivo models of stroke and diabetes. Bromocriptine analogs with reduced dopamine receptor activity retain similar efficacy in stabilizing the ER proteome, indicating a non-canonical mechanism of action. This study describes a strategic approach to identify small-molecule drugs capable of improving ER proteostasis in human disease conditions.Peer reviewe

Kinetic and Structural Investigations of Novel Inhibitors of Human Epithelial 15-Lipoxygenase-2

Human epithelial 15-lipoxygenase-2 (h15-LOX-2, ALOX15B) is expressed in many tissues and has been implicated in atherosclerosis, cystic fibrosis and ferroptosis. However, there are few reported potent/selective inhibitors that are active ex vivo. In the current work, we report newly discovered molecules that are more potent and structurally distinct from our previous inhibitors, MLS000545091 and MLS000536924 (Jameson et al, PLoS One, 2014, 9, e104094), in that they contain a central imidazole ring, which is substituted at the 1-position with a phenyl moiety and with a benzylthio moiety at the 2-position. The initial three molecules were mixed-type, non-reductive inhibitors, with IC(50) values of 0.34 ± 0.05 μM for MLS000327069, 0.53 ± 0.04 μM for MLS000327186 and 0.87 ± 0.06 μM for MLS000327206 and greater than 50-fold selectivity versus h5-LOX, h12-LOX, h15-LOX-1, COX-1 and COX-2. A small set of focused analogs was synthesized to demonstrate the validity of the hits. In addition, a binding model was developed for the three imidazole inhibitors based on computational docking and a co-structure of h15-LOX-2 with MLS000536924. Hydrogen/deuterium exchange (HDX) results indicate a similar binding mode between MLS000536924 and MLS000327069, however, the latter restricts protein motion of helix-α2 more, consistent with its greater potency. Given these results, we designed, docked, and synthesized novel inhibitors of the imidazole scaffold and confirmed our binding mode hypothesis. Importantly, four of the five inhibitors mentioned above are active in an h15-LOX-2/HEK293 cell assay and thus they could be important tool compounds in gaining a better understanding of h15-LOX-2’s role in human biology. As such, a suite of similar pharmacophores that target h15-LOX-2 both in vitro and ex vivo are presented in the hope of developing them as therapeutic agents

Quantitative High-Throughput Screening Identifies 8-Hydroxyquinolines as Cell-Active Histone Demethylase Inhibitors

Small molecule modulators of epigenetic processes are currently sought as basic probes for biochemical mechanisms, and as starting points for development of therapeutic agents. N(epsilon)-Methylation of lysine residues on histone tails is one of a number of post-translational modifications that together enable transcriptional regulation. Histone lysine demethylases antagonize the action of histone methyltransferases in a site- and methylation state-specific manner. N(epsilon)-Methyllysine demethylases that use 2-oxoglutarate as co-factor are associated with diverse human diseases, including cancer, inflammation and X-linked mental retardation; they are proposed as targets for the therapeutic modulation of transcription. There are few reports on the identification of templates that are amenable to development as potent inhibitors in vivo and large diverse collections have yet to be exploited for the discovery of demethylase inhibitors

Environmentally benign reaction: Synthesis of sydnone chaIcones under solvent-free conditions

2556-2557An easy, simple and eco-friendly synthesis of 4-(1'-oxo-3'-aryl-2'-propenyl)-3-arylsydnones is reported by grinding 4-acetyl-3-arylsydnones with various aryl aldehydes in a mortar with pestle

One pot reaction: Synthesis, characterization and biological activity of 3-alkyl/aryl-9- substituted 1,2,4-triazolo[3,4-<i>b</i>] [1,3,4]quinolinothiadiazepines

211-214Reaction of 6-substituted-2-chloro-3-formylquinoline 1 and 3-substituted-4-amino-5-mercapto-1,2,4-triazole 2 gave the novel thiadiazepine derivatives 5 rather than expected Schiff bases 4. Alternatively, compounds 5 were also prepared by the reaction of 2 with 6-substitutcri quinolones 3. The structures of the newly synthesized compounds have been proposed on the basis of elemental analysis, IR,1H NMR and mass spectral data. Some of the new synthetic compounds were also screened for their antibacterial and antifungal activity. Most of them showed significant activity

<span style="font-size:14.0pt;font-family:"Times New Roman";color:#1A1A1A;mso-bidi-font-weight: bold" lang="EN-IN">Reaction of anilinoacet hydrazides with <span style="font-size:14.0pt;font-family:"Times New Roman";mso-fareast-font-family: HiddenHorzOCR;color:#1A1A1A;mso-bidi-font-weight:bold" lang="EN-IN">α<span style="font-size:14.0pt;font-family:HiddenHorzOCR;mso-hansi-font-family: "Times New Roman";mso-bidi-font-family:HiddenHorzOCR;color:#1A1A1A;mso-bidi-font-weight: bold" lang="EN-IN">,<span style="font-size:14.0pt;font-family:"Times New Roman"; mso-fareast-font-family:HiddenHorzOCR;color:#1A1A1A;mso-bidi-font-weight:bold" lang="EN-IN">β<span style="font-size:14.0pt;font-family:HiddenHorzOCR;mso-hansi-font-family: "Times New Roman";mso-bidi-font-family:HiddenHorzOCR;color:#1A1A1A;mso-bidi-font-weight: bold" lang="EN-IN">-acetylenic <span style="font-size:14.0pt;font-family: "Times New Roman";color:#1A1A1A;mso-bidi-font-weight:bold" lang="EN-IN">ketones and structural characterization of new compounds </span></span></span></span></span></span>

597-602Reactions of 1-aryl-3 -(5-nitro-2-thienyl/furyl)-2-propyne-1-one 3 with anilinoacet hydrazides 4<span style="font-size:14.0pt;font-family: " times="" new="" roman";color:#1a1a1a;mso-bidi-font-weight:bold"="" lang="EN-IN"> give the 1-anilinoacetyl-3-(5-nitro-2-thienyl/furyl)-5-aryl-5-hydroxypyrazolines 5-6 rather than the expected pyrazoles 7-<b style="mso-bidi-font-weight: normal">8. Various attempts have been made for the conversion of 5-6 to 7-8. The studies also reveal that the carbonyl group in 4 is responsible for the formation of hydroxypyrazolines. The structures of newly synthesized compounds have been proposed on the basis of elemental analysis and spectral data, and in some cases through the synthesis of authentic samples by alternative routes. </span

Room-Temperature, Copper-Free Sonogashira Reactions Facilitated by Air-Stable, Monoligated Precatalyst [DTBNpP] Pd(crotyl)Cl

A novel application of [DTBNpP] Pd­(crotyl)­Cl (DTBNpP = di-tert-butylneopentylphosphine) (P2), an air-stable, commercially available palladium precatalyst that allows rapid access to a monoligated state, has been identified for room-temperature, copper-free Sonogashira couplings of challenging aryl bromides and alkynes. The mild reaction conditions with TMP in dimethyl sulfoxide afford up to 97% yields, excellent functional group tolerability, and broad reaction compatibility with access to one-pot indole formation

Kinetic and structural investigations of novel inhibitors of human epithelial 15-lipoxygenase-2

Human epithelial 15-lipoxygenase-2 (h15-LOX-2, ALOX15B) is expressed in many tissues and has been implicated in atherosclerosis, cystic fibrosis and ferroptosis. However, there are few reported potent/selective inhibitors that are active ex vivo. In the current work, we report newly discovered molecules that are more potent and structurally distinct from our previous inhibitors, MLS000545091 and MLS000536924 (Jameson et al, PLoS One, 2014, 9, e104094), in that they contain a central imidazole ring, which is substituted at the 1-position with a phenyl moiety and with a benzylthio moiety at the 2-position. The initial three molecules were mixed-type, non-reductive inhibitors, with IC values of 0.34 ± 0.05 μM for MLS000327069, 0.53 ± 0.04 μM for MLS000327186 and 0.87 ± 0.06 μM for MLS000327206 and greater than 50-fold selectivity versus h5-LOX, h12-LOX, h15-LOX-1, COX-1 and COX-2. A small set of focused analogs was synthesized to demonstrate the validity of the hits. In addition, a binding model was developed for the three imidazole inhibitors based on computational docking and a co-structure of h15-LOX-2 with MLS000536924. Hydrogen/deuterium exchange (HDX) results indicate a similar binding mode between MLS000536924 and MLS000327069, however, the latter restricts protein motion of helix-α2 more, consistent with its greater potency. Given these results, we designed, docked, and synthesized novel inhibitors of the imidazole scaffold and confirmed our binding mode hypothesis. Importantly, four of the five inhibitors mentioned above are active in an h15-LOX-2/HEK293 cell assay and thus they could be important tool compounds in gaining a better understanding of h15-LOX-2\u27s role in human biology. As such, a suite of similar pharmacophores that target h15-LOX-2 both in vitro and ex vivo are presented in the hope of developing them as therapeutic agents

Discovery of Potent and Selective Inhibitors of Human Reticulocyte 15-Lipoxygenase-1

There are a variety of lipoxygenases in the human body (hLO), each having a distinct role in cellular biology. Human reticulocyte 15-lipoxygenase-1 (15-hLO-1), which catalyzes the dioxygenation of 1,4-cis,cis-pentadiene-containing polyunsaturated fatty acids, is implicated in a number of diseases including cancer, atherosclerosis, and neurodegenerative conditions. Despite the potential therapeutic relevance of this target, few inhibitors have been reported that are both potent and selective. To this end, we have employed a quantitative high-throughput (qHTS) screen against ∼74000 small molecules in search of reticulocyte 15-hLO-1 selective inhibitors. This screen led to the discovery of a novel chemotype for 15-hLO-1 inhibition, which displays nM potency and is &gt;7500-fold selective against the related isozymes, 5-hLO, platelet 12-hLO, epithelial 15-hLO-2, ovine cyclooxygenase-1, and human cyclooxygenase-2. In addition, kinetic experiments were performed which indicate that this class of inhibitor is tight binding, reversible, and appears not to reduce the active-site ferric ion