The discovery of compounds with antimicrobial properties is crucial to prevent the growing resistance to antibiotics. To search for drugs, the pharmaceutical industry utilises the approach of finding ligands that bind (and thus inhibit) the target protein. In order to detect interactions with other cellular components and thus avoid compounds with potentially toxic side effects, we used a small molecule to protein targeting approach in our laboratory. In this thesis, we aimed to identify the protein targets of the small molecule 4-(2-aminoethyl)-1-(pyridin-2-yl)-1H-pyrzol-5-ol, which was shown to inhibit the growth of Escherichia coli laboratory strain DH5α. The compound was immobilized on agarose beads and the prepared column was used for affinity chromatography with which we isolated interacting proteins from the E. coli lysate. Eluted fractions were analyzed by SDS-PAGE and sent for protein identification by mass spectrometry. Two prominent bands on the gel were identified as threonine dehydrogenase and the Fe-S subunit of succinate dehydrogenase. According to the literature, the possible mechanism for bacteriostatic action of the compound is inhibition of threonine dehydrogenase which is involved in the biosynthesis of signalling molecules. Inhibition of succinate dehydrogenase is unlikely to affect E. coli growth.
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