Native Mass Spectrometry using an electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (ESI-FTICR-MS) can detect protein in its native folded state and can also detect non-covalent protein-ligand complexes.
We have harnessed the chemical diversity of natural products for fragment-based drug screening. We have reported 96 low molecular weight natural products identified as binding partners of 32 putative malarial targets. Seventy-nine (79) fragments have direct growth inhibition on Plasmodium falciparum at concentrations that are promising for development of fragment hits against these protein targets. This adds a fragment library to the published HTS active libraries in the public domain.1 Subsequently, we identified 26 low molecular weight natural products that bind to 9 proteins from Mycobacterium tuberculosis.
Phenotypic screening against M. tuberculosis H37Rv and the TB target Lipoamide Dehydrogenase (Lpd) produced 452 fractions showing a MIC following 11-point dose response analysis. The Lpd screen gave 169 fractions that inhibited Lpd in a duplicate point assay following a single point HTS.
We are using the phenotypic active fractions to conduct target identification using a panel of cloned and expressed Mycobacterium proteins.
[1] Vu, H.; Pedro, L.; Mak, T.; McCormick, B.; Rowley, J.; Liu, M.; Capua, A. D.; Williams-Noonan, B.; Pham, N. B.; Pouwer, R.; Nguyen, B.; Andrews, K. T.; Skinner-Adams, T.; Kim, J.; Hol, W.; Hui, R.; Crowther, G. J.; Voorhis, W. C. V.; Quinn, R. J., ACS Infect. Dis. 2018, 10.1021/acsinfecdis.7b00197.