Characterization and Inhibition of 1-Deoxy-d-Xylulose 5-Phosphate Reductoisomerase: A Promising Drug Target in and .

The ESKAPE pathogens comprise a group of multidrug-resistant bacteria that are the leading cause of nosocomial infections worldwide. The prevalence of antibiotic resistant strains and the relative ease by which bacteria acquire resistance genes highlight the continual need for the development of novel antibiotics against new drug targets. The methylerythritol phosphate (MEP) pathway is an attractive target for the development of new antibiotics.

Inhibition of the Methylerythritol Phosphate Pathway of Isoprenoid Biosynthesis by α-Phenyl-Substituted Reverse Fosmidomycin Analogues.

Fosmidomycin inhibits IspC (1-deoxy-d-xylulose 5-phosphate reductoisomerase), the first committed enzyme in the methylerythritol phosphate (MEP) pathway of isoprenoid biosynthesis. The MEP pathway of isoprenoid biosynthesis is essential to the causative agent of the plague, , and is entirely distinct from the corresponding mammalian pathway. To further drug development, we established structure-activity relationships of fosmidomycin analogues by assessing a suite of 17 α-phenyl-substituted reverse derivatives of fosmidomycin against IspC.

Discovery of novel inhibitors of multidrug-resistant Acinetobacter baumannii.

The recent emergence of multidrug-resistant Acinetobacter baumannii strains and the non-efficacy of currently available antibiotics against such infections have led to an urgent need for the development of novel antibacterials. In an effort to address this problem, we have identified three novel inhibitors, namely, D5, D12 and D6 using in silico screening with a homology model of the outer membrane protein W2 (OmpW2) from A. baumannii, as the proposed new drug target.

A conformational change in the peripheral anionic site of Torpedo californica acetylcholinesterase induced by a bis-imidazolium oxime.

As part of ongoing efforts to design improved nerve agent antidotes, two X-ray crystal structures of Torpedo californica acetylcholinesterase (TcAChE) bound to the bis-pyridinium oxime, Ortho-7, or its experimental bis-imidazolium analogue, 2BIM-7, were determined. Bis-oximes contain two oxime groups connected by a hydrophobic linker. One oxime group of Ortho-7 binds at the entrance to the active-site gorge near Trp279, and the second binds at the bottom near Trp84 and Phe330.

Evaluation and computational characterization of the facilitated transport of Glc carbon C-1 oxime reactivators across a blood brain barrier model.

We are evaluating a facilitative transport strategy to move oximes across the blood brain barrier (BBB) to reactivate inhibited brain acetylcholinesterase (AChE). We selected glucose (Glc) transporters (GLUT) for this purpose as these transporters are highly represented in the BBB. Glc conjugates have successfully moved drugs across the BBB and previous work has shown that Glc-oximes (sugar-oximes, SOxs) can reduce the organophosphonate induced hypothermia response.

Aerosolized delivery of oxime MMB-4 in combination with atropine sulfate protects against soman exposure in guinea pigs.

We evaluated the efficacy of aerosolized acetylcholinesterase (AChE) reactivator oxime MMB-4 in combination with the anticholinergic atropine sulfate for protection against respiratory toxicity and lung injury following microinstillation inhalation exposure to nerve agent soman (GD) in guinea pigs. Anesthetized animals were exposed to GD (841 mg/m(3), 1.2 LCt(50)) and treated with endotracheally aerosolized MMB-4 (50 µmol/kg) plus atropine sulfate (0.

Hydrolysis potential of recombinant human skin and kidney prolidase against diisopropylfluorophosphate and sarin by in vitro analysis.

Human prolidase (PROL), which has structural homology to bacterial organophosphate acid anhydrolase that hydrolyze organophosphates and nerve agents has been proposed recently as a potential catalytic bioscavenger. To develop PROL as a catalytic bioscavenger, we evaluated the in vitro hydrolysis efficiency of purified recombinant human PROL against organophosphates and nerve agents. Human liver PROL was purified by chromatographic procedures, whereas recombinant human skin and kidney PROL was expressed in Trichoplusia ni larvae, affinity purified and analyzed by gel electrophoresis.

In vitro efficacy of paraoxonase 1 from multiple sources against various organophosphates.

Paraoxonase 1 (PON1) has been described as a potential catalytic bioscavenger due to its ability to hydrolyze organophosphate (OP) insecticides and nerve agents. In vitro catalytic efficiency of purified human and rabbit serum PON1 against different OP substrates was compared to human recombinant PON1, expressed in Trichoplusia ni larvae. Highly purified human and rabbit serum PON1s were prepared by multiple chromatography methods.

Efficient hydrolysis of the chemical warfare nerve agent tabun by recombinant and purified human and rabbit serum paraoxonase 1.

Paraoxonase 1 (PON1) has been described as an efficient catalytic bioscavenger due to its ability to hydrolyze organophosphates (OPs) and chemical warfare nerve agents (CWNAs). It is the future most promising candidate as prophylactic medical countermeasure against highly toxic OPs and CWNAs. Most of the studies conducted so far have been focused on the hydrolyzing potential of PON1 against nerve agents, sarin, soman, and VX.