Faster diffusive dynamics of histone-like nucleoid structuring proteins in live bacteria caused by silver ions.

Faster diffusive dynamics of histone-like nucleoid structuring proteins in live bacteria caused by silver ions. Appl Environ Microbiol. 2020 Jan 17;: Authors: Sadoon AA, Khadka P, Freeland J, Gundampati RK, Manso R, Ruiz M, Krishnamurthi VR, Thallapuranam SK, Chen J, Wang Y Abstract The antimicrobial activity and mechanism of silver ions (Ag+) have gained broad attention in recent years. However, dynamic studies are rare in this field. Here, we report our measurement of the effects of Ag+ ions on the dynamics of histone-like nucleoid structuring (H-NS) proteins in live bacteria using single-particle tracking photoactivated localization microscopy (sptPALM). It was found that treating the bacteria with Ag+ ions led to faster diffusive dynamics of H-NS proteins. Several techniques were used to understand the mechanism of the observed faster dynamics. Electrophoretic mobility shift assay on purified H-NS proteins indicated that Ag+ ions weaken the binding between H-NS proteins and DNA. Isothermal titration calorimetry confirmed that DNA and Ag+ ions interact directly. Our recently developed sensing method based on bent DNA suggested that Ag+ ions caused dehybridization of double-stranded DNA (i.e., dissociation into single strands). These evidences led us to a plausible mechanism for the observed faster dynamics of H-NS proteins in live bacteria when subjected to Ag+ ions: Ag+-induced DNA dehybridization weakens the binding between H-NS...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research