Magnetic Microbead Affinity Selection Screening: Development, Application, and Evaluation

Contemporary natural product drug discovery relies on bioassay guided fractionation. This technique – while exhaustive – is expensive and time consuming. By introducing mass spectrometry earlier in the natural product drug discovery workflow, many of these costs can be mitigated. Magnetic Microbead Affinity Selection Screening (MagMASS) was developed to shortcut bioassay guided fractionation. This assay immobilizes protein targets to magnetic microbeads for use as bioaffinity chromatography. Following incubation with the natural product extracts and washing to remove nonspecific binders, the ligands are collected and analyzed using liquid chromatography-mass spectrometry. MagMASS was developed and optimized using RXRα as an anti-inflammatory target using standards. Once the assay was operational, MagMASS using 15-lipoxygenase (15-LOX) was carried out to develop a workflow for targeting natural products. Upon finding a botanical ligand for 15-LOX as proof of concept, MagMASS was used to screen 900 actinomycetes extracts for ligands of fructose-1,6-bisphosphatase as an evaluation of this technique as a high-throughput drug discovery system.