Discrimination of Potent Inhibitors of Toxoplasma gondii Enoyl-Acyl Carrier Protein Reductase by a Thermal Shift Assay

Many microbial pathogens rely on a type II fatty acid synthesis (FASII) pathway that is distinct from the type I pathway found in humans. Enoyl-acyl carrier protein reductase (ENR) is an essential FASII pathway enzyme and the target of a number of antimicrobial drug discovery efforts. The biocide triclosan is established as a potent inhibitor of ENR and has been the starting point for medicinal chemistry studies. We evaluated a series of triclosan analogues for their ability to inhibit the growth of Toxoplasma gondii, a pervasive human pathogen, and its ENR enzyme (TgENR). Several compounds that inhibited TgENR at low nanomolar concentrations were identified but could not be further differentiated because of the limited dynamic range of the TgENR activity assay. Thus, we adapted a thermal shift assay (TSA) to directly measure the dissociation constant (Kd) of the most potent inhibitors identified in this study as well as inhibitors from previous studies. Furthermore, the TSA allowed us to determine the mode of action of these compounds in the presence of the reduced nicotinamide adenine dinucleotide (NADH) or nicotinamide adenine dinucleotide (NAD+) cofactor. We found that all of the inhibitors bind to a TgENR–NAD+ complex but that they differed in their dependence on NAD+ concentration. Ultimately, we were able to identify compounds that bind to the TgENR–NAD+ complex in the low femtomolar range. This shows how TSA data combined with enzyme inhibition, parasite growth inhibition data, and ADMET predictions allow for better discrimination between potent ENR inhibitors for the future development of medicine

Third party consultation: a method for the study and resolution of conflict

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66597/2/10.1177_002200277201600105.pd

Shape Controlled Electroless Plating of Hetero Nanostructures AgCu and AgNi Decorated Ag Nanoplates on Carbon Fibers as Catalysts for the Oxygen Evolution Reaction

This study addresses the potential of combining multiple electroless plating reactions for homogeneous decoration of three dimensional carbon fibers CFs with shape controlled AgNi and AgCu bimetallic nanostructures. Morphology, crystal structure, and composition of the obtained bimetallic nanostructures were systemically examined by various spectroscopic and microscopic techniques including scanning electron microscopy, transmission electron microscopy, X ray diffraction, and X ray photoelectron spectroscopy. The electrocatalytic performance of the synthesized materials was investigated for the oxygen evolution reaction OER . AgCu and AgNi bimetallic surfaces showed superior activity and stability compared to pristine Ag, Ni, or Cu. These observed enhancements on the bimetallic nanostructures are attributed to the synergistic effect between the elements present. AgNi nanoplate decorated CFs exhibited the highest activity toward OER, which is attributed to the key role of Ag in stabilizing and increasing the number of amp; 946; NiOOH surface sites, which are the most relevant OER active Ni specie