Affinity selection-mass spectrometry discovery of small ligands for lysosomal storage disease targets

Overview

This solution offers affinity selection-mass spectrometry (AS-MS) screening services for the rapid discovery of small molecule ligands targeting proteins and substrates relevant to lysosomal storage diseases (LSDs). Developed at Oregon State University, the platform uses two complementary techniques—pulsed ultrafiltration mass spectrometry (PUF MS) and magnetic microbead affinity selection screening (MagMASS)—to screen natural product extracts, combinatorial libraries, and other compound mixtures against challenging macromolecular targets including glycosaminoglycans, sphingolipids, and lysosomal proteins.

The approach addresses key limitations of conventional high-throughput screening (HTS) by eliminating the need for known ligands, supporting allosteric binding sites, and working with any buffer or pH—including the acidic conditions found in lysosomes. It is particularly valuable for identifying ligands that can serve as leads for imaging agents or therapeutics targeting LSD-related pathways.

Technical specifications

How it works:

• Compound mixtures (natural product extracts, combinatorial pools) are incubated with the target macromolecule
• Ligands bind to the target during incubation
• Unbound compounds are removed via ultrafiltration, size exclusion, or magnetic separation
• Bound ligands are released and characterized using high-resolution tandem mass spectrometry (MS/MS)

Key advantages over conventional HTS:

• Works with any target type, including glycosaminoglycans, sphingolipids, and lysosomal proteins
• Discovers allosteric ligands in addition to orthosteric binders
• Compatible with natural products that may exhibit fluorescence or absorbance interference in conventional assays
• Operates in any buffer at any pH, including lysosomal conditions
• Faster and less expensive than HTS through mixture-based screening rather than individual compound testing
• No requirement for known reference ligands to establish assays
• Targets screened at micromolar concentrations to detect ligands with micromolar or better binding affinity

Custom assay development:

A new AS-MS assay can be developed for a different target on a monthly basis, with ligand screening proceeding once the assay is validated.

Technology readiness level

The AS-MS platform has been validated through published research, including the discovery of cannabinoids that bind to the SARS-CoV-2 spike protein and inhibit cell entry. The methodology is established and operational, with demonstrated capability to handle complex targets and diverse compound libraries. Future validation efforts focus on screening natural product extracts from botanicals, microbial cultures, and fungi against representative LSD targets to identify ligands suitable for imaging agent development. The platform is positioned for collaborative research partnerships to expand ligand discovery across the full range of lysosomal storage disease targets.