Mechanism of the antimicrobial activity induced by phosphatase inhibitor sodium ortho-vanadate.

The present study describes a novel antimicrobial mechanism based on Sodium Orthovanadate (SOV), an alkaline phosphatase inhibitor. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) were employed to examine the surface morphologies of the test organism, Escherichia coli (E. coli), during various antibacterial phases. Our results indicated that SOV kills bacteria by attacking cell wall growth and development, leaving E. coli 's outer membrane intact. Our antimicrobial test indicated that the MIC of SOV for both E. coli and Lactococcus lactis (L. lactis) is 40 μM. A combination of quantum mechanical calculations and vibrational spectroscopy revealed that divanadate from SOV strongly coordinates with Ca2+ and Mg2+, which are the activity centers for the phosphatase that regulates bacterial cell wall synthesis. The current study is the first to propose the antibacterial mechanism caused by SOV attacking cell wall. Sodium orthovanadate inhibits undecaprenyldiphosphate phosphatases by forming complex with them, and terminates the polymerization of peptidoglycan leading to cell wall destruction and consequently, cell death. [Display omitted] • Sodium ortho-vanadate inhibits phosphatase that regulates bacterial cell wall synthesis. • Sodium ortho-vanadate kills bacteria by targeting cell wall. • Cell images indicate the cell wall damage but intact outer membrane. • Synergetic antimicrobial activity with phosphatase nanozyme [ABSTRACT FROM AUTHOR]