20.500.12556/RUL-176702 Cooperativity in Escherichia coli L-threonine dehydrogenase and its inhibition by an antibacterial N-pyridylpyrazolone derivative Antibiotic resistance is an increasing concern in modern healthcare. Therefore, it is important to identify novel antimicrobial agents and new molecular targets for such compounds. Here, we describe the identification of an N-pyridylpyrazolone derivative, 4-(2-aminoethyl)-2-(pyridin-2-yl)-1,2-dihydro-3H-pyrazol-3-one dihydrochloride (compound 1), which is effective against Gram-positive and Gram-negative bacteria and inhibits the enzymatic activity of Escherichia coli L-threonine dehydrogenase (TDH). To characterize its interaction with compound 1, TDH was overexpressed in E. coli. The recombinant enzyme was shown to exist in dilute solution in equilibrium between dimeric and tetrameric forms, with a K$_d$ value for the dimer/tetramer transition of 3 ± 1 nM, and to bind L-threonine cooperatively with a Hill coefficient of 1.4. Compound 1 acted as a partial mixed inhibitor of TDH with an EC$_{50}$ value of 47 ± 16 µM and did not affect the equilibrium between oligomeric states. Altogether, these findings identify compound 1 as a promising starting point for the development of novel antibiotics and as a tool compound for studying the functional properties of TDH. allostery enzyme kinetics partial inhibition mixed inhibition homotetramer antibiotics mass photometry alosterija encimska kinetika delna inhibicija mešana inhibicija homotetramer antibiotiki masna fotometrija true false true Angleški jezik Slovenski jezik Članek v reviji 2025-12-09 13:24:33 2025-12-09 13:24:34 2025-12-23 04:13:09 0000-00-00 00:00:00 2025 0 0 10 str. iss. 23, art. 11751 Vol. 26 Dec. 2025 0000-00-00 Zaloznikova Objavljeno apc 0000-00-00 0000-00-00 0000-00-00 577.15:547.8 1422-0067 10.3390/ijms262311751 260536579 RAZ_Obaha_Ana_2025.pdf RAZ_Obaha_Ana_2025.pdf 1 4BE4880C24B042A63431F10AA1DEB83B 7f8d3b27d279da189324bc299d4317ea0ae20b1eeab2e6cb7a90ecef74eb6296 17b6e21a-d4fa-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=223214 https://www.mdpi.com/1422-0067/26/23/11751 1 9bce00c2-d4f9-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=223213 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0