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

• Main Authors: Yang Xiang, Yue-Juan Zhang, Ying Ge, Yajun Zhou, Cheng Chen, Weixiao Yuan Wahlgren, Xiangshi Tan, Xi Chen, Ke-Wu Yang
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Biomolecules
• Subjects: antibiotic resistance; metallo-β-lactamase vim-2 inhibitor; 2-triazolylthioacetamides; thermodynamics; crystallographic study
• Online Access: https://www.mdpi.com/2218-273X/10/1/72

Inhibition of &#946;-lactamases presents a promising strategy to restore the &#946;-lactams antibacterial activity to resistant bacteria. In this work, we found that aromatic carboxyl substituted 2-triazolylthioacetamides <b>1a</b>&#8722;<b>j</b> inhibited VIM-2, exhibiting an IC₅₀ value in the range of 20.6&#8722;58.6 &#956;M. 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. <b>1a</b>&#8722;<b>j</b> (16 mg/mL) restored the antibacterial activity of cefazolin against <i>E. coli</i> cell expressing VIM-2, resulting in a 4&#8722;8-fold reduction in MICs. The isothermal titration calorimetry (ITC) characterization suggested that the primary binding 2-triazolylthioacetamide (<b>1b</b>, <b>1c</b>, or <b>1h</b>) to VIM-2 was a combination of entropy and enthalpy contributions. Further, the crystal structure of VIM-2 in complex with <b>1b</b> was obtained by co-crystallization with a hanging-drop vapour-diffusion method. The crystal structure analysis revealed that <b>1b</b> 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 &#960;-&#960; 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 M&#946;Ls inhibitors.