Kinetic, Thermodynamic, and Crystallographic Studies of 2-Triazolylthioacetamides as Verona Integron-Encoded Metallo-β-Lactamase 2 (VIM-2) Inhibitor

Abstract

Inhibition of β-lactamases presents a promising strategy to restore the β-lactams antibacterial activity to resistant bacteria. In this work, we found that aromatic carboxyl substituted 2-triazolylthioacetamides 1a–j inhibited VIM-2, exhibiting an IC50 value in the range of 20.6–58.6 μM. The structure-activity relationship study revealed that replacing the aliphatic carboxylic acid with aromatic carboxyl improved the inhibitory activity of 2-triazolylthioacetamides against VIM-2. 1a–j (16 mg/mL) restored the antibacterial activity of cefazolin against E. coli cell expressing VIM-2, resulting in a 4–8-fold reduction in MICs. The isothermal titration calorimetry (ITC) characterization suggested that the primary binding 2-triazolylthioacetamide (1b, 1c, or 1h) to VIM-2 was a combination of entropy and enthalpy contributions. Further, the crystal structure of VIM-2 in complex with 1b was obtained by co-crystallization with a hanging-drop vapour-diffusion method. The crystal structure analysis revealed that 1b bound to two Zn(II) ions of the enzyme active sites, formed H-bound with Asn233 and structure water molecule, and interacted with the hydrophobic pocket of enzyme activity center utilizing hydrophobic moieties; especially for the phenyl of aromatic carboxyl which formed π-π stacking with active residue His263. These studies confirmed that aromatic carboxyl substituted 2-triazolylthioacetamides are the potent VIM-2 inhibitors scaffold and provided help to further optimize 2-triazolylthioacetamides as VIM-2 even or broad-spectrum MβLs inhibitors.

Curcumin inhibits liquid–liquid phase separation of fused in sarcoma and attenuates the sequestration of pyruvate kinase to restore cellular metabolism

“…Isothermal titration microcalorimetry (ITC) was performed as reported. 22 10 μM FUS solution and 100 μM curcumin solution were prepared with buffers containing 50 mM Tris–HCl and 150 mM NaCl, respectively. Then 300 μL FUS solution and 70 μL curcumin solution were added to the sample cell, and the reaction temperature was 37 °C.…”

β-Lactamases: Sequence, Structure, Function, and Inhibition

“…Xiang et al [11] also studied inhibition of VIM-2 by similar compounds, 2-triazolylthioa cetamides. Several compounds were able to decrease the MIC of cefazolin 4-to 8-fold against VIM-2-expressing E. coli.…”