Identification of Phosphoribosyl-AMP cyclohydrolase,as drug target and its inhibitors in Brucella melitensis bv. 1 16M using metabolic pathway analysis

Brucella melitensis is a pathogenic Gram-negative bacterium which is known for causing zoonotic diseases (Brucellosis). The organism is highly contagious and has been reported to be used as bioterrorism agent against humans. Several antibiotics and vaccines have been developed but these antibiotics have exhibited the sign of antibiotic resistance or ineffective at lower concentrations, which imposes an urgent need to identify the novel drugs/drug targets against this organism. In this work, metabolic pathways analysis has been performed with different filters such as non-homology with humans, essentially of genes and choke point analysis, leading to identification of novel drug targets. A total of 18 potential drug target proteins were filtered out and used to develop the high confidence protein–protein interaction network The Phosphoribosyl-AMP cyclohydrolase (HisI) protein has been identified as potential drug target on the basis of topological parameters. Further, a homology model of (HisI) protein has been developed using Modeller with multiple template (1W6Q (48%), 1ZPS (55%), and 2ZKN (48%)) approach and validated using PROCHECK and Verify3D. The virtual high throughput screening (vHTS) using DockBlaster tool has been performed against 16,11,889 clean fragments from ZINC database. Top 500 molecules from DockBlaster were docked using Vina. The docking analysis resulted in ZINC04880153 showing the lowest binding energy (?9.1 kcal/mol) with the drug target. The molecular dynamics study of the complex HisI-ZINC04880153 was conducted to analyze the stability and fluctuation of ligand within the binding pocket of HisI. The identified ligand could be analyzed in the wet-lab based experiments for future drug discovery.     

In vivo alpha-adrenergic responses and troponin I phosphorylation: anesthesia interactions.

The mechanisms by which alpha-adrenergic stimulation of the heart in vivo can cause contractile dysfunction are not well understood. We hypothesized that alpha-adrenergic-mediated contractile dysfunction is mediated through protein kinase C phosphorylation of troponin I, which in in vitro experiments has been shown to reduce actomyosin Mg-ATPase activity. We studied pressure-volume loops in transgenic mice expressing mutant troponin I lacking protein kinase C phosphorylation sites and hypothesized altered responses to phenylephrine. As anesthesia agents can produce markedly different effects on contractility, we studied two agents: avertin and alpha-chloralose-urethane. With alpha-chloralose-urethane, at baseline, there were no contractile abnormalities in the troponin I mutants. Phenylephrine produced a 50% reduction in end-systolic elastance in wild-type controls, although a 9% increase in troponin I mutants (P <0.05). Avertin was associated with reduced contractility compared with alpha-chloralose-urethane. Avertin anesthesia, at baseline, produced a reduction in end-systolic elastance by 31% in the troponin I mutants compared with wild-type (P <0.05), and this resulted in further marked systolic and diastolic dysfunction with phenylephrine in the troponin I mutants. Dobutamine produced no significant difference in the contractile phenotype of the transgenic mice with either anesthetic regimen. In conclusion, these data (alpha-chloralose-urethane) demonstrate that alpha-adrenergic-mediated force reduction is mediated through troponin I protein kinase C phosphorylation. beta-Adrenergic responses are not mediated through this pathway. Altering the myofilament force-calcium relationship may result in in vivo increased sensitivity to negative inotropy. Thus choice of a negative inotropic anesthetic agent (avertin) with phenylephrine can lead to profound contractile dysfunction.     

Expression, purification, refolding and characterization of a putative lysophospholipase from Pyrococcus furiosus: retention of structure and lipase/esterase activity in the presence of water-miscible organic solvents at high temperatures

A putative lysophospholipase (PF0480) encoded by the Pyrococcus furiosus genome has previously been cloned and expressed in Escherichia coli. Studies involving crude extracts established the enzyme to be an esterase; however, owing presumably to its tendency to precipitate into inclusion bodies, purification and characterization have thus far not been reported. Here, we report the overexpression and successful recovery and refolding of the enzyme from inclusion bodies. Dynamic light scattering suggests that the enzyme is a dimer, or trimer, in aqueous solution. Circular dichroism and fluorescence spectroscopy show, respectively, that it has mixed beta/alpha structure and well-buried tryptophan residues. Conformational changes are negligible over the temperature range of 30–80 °C, and over the concentration range of 0–50% (v/v) of water mixtures with organic solvents such as methanol, ethanol and acetonitrile. The enzyme is confirmed to be an esterase (hydrolyzing p-NP-acetate and p-NP-butyrate) and also shown to be a lipase (hydrolyzing p-NP-palmitate), with lipolytic activity being overall about 18- to 20-fold lower than esterase activity. Against p-NP-palmitate the enzyme displays optimally activity at pH 7.0 and 70 °C. Remarkably, over 50% activity is retained at 70 °C in the presence of 25% acetonitrile. The high organic solvent stability and thermal stability suggest that this enzyme may have useful biodiesel-related applications, or applications in the pharmaceutical industry, once yields are optimized.     

Synthesis and structure based optimization of novel Akt inhibitors

Based on a high throughput screening hit, pyrrolopyrimidine inhibitors of the Akt kinase are explored. X-ray co-crystal structures of two lead series results in the understanding of key binding interactions, the design of new lead series, and enhanced potency. The syntheses of these series and their biological activities are described. Spiroindoline 13j is found to have an Akt1 kinase IC(50) of 2.4+/-0.6 nM, Akt cell potency of 50+/-19 nM, and provides 68% inhibition of tumor growth in a mouse xenograft model (50 mg/kg, qd, po).     

Discovery of spirocyclic secondary amine-derived tertiary ureas as highly potent,selective and bioavailable soluble epoxide hydrolase inhibitors

Spirocyclic secondary amine-derived trisubstituted ureas were identified as highly potent, bioavailable and selective soluble epoxide hydrolase (sEH) inhibitors. Despite good oral exposure and excellent ex vivo target engagement in blood, one such compound, rac-1a, failed to lower blood pressure acutely in spontaneously hypertensive rats (SHRs). This study posed the question as to whether sEH inhibition provides a robust mechanism leading to a significant antihypertensive effect.