Opposing Effects of PhoPQ and PmrAB on the Properties of <i>Salmonella enterica</i> serovar Typhimurium: Implications on Resistance to Antimicrobial Peptides
Tal Shprung, Naiem Ahmad Wani, Miriam Wilmes, Maria Luisa Mangoni, Arkadi Bitler, Eyal Shimoni, Hans‐Georg Sahl, Yechiel Shai
Abstract
. The knockout of PhoPQ made the bacteria more susceptible to AMPs by making the surface less rigid, more polarized, and permeable with a slightly more negatively charged cell wall. In addition, the periplasmic space is thinner. In contrast, the knockout of PmrAB did not affect its susceptibility, while it made the bacterial outer layer very rigid, less polarized, and less permeable than the other two mutants, with a negatively charged cell wall similar to the WT. Overall, the data suggest that the coexistence of systems with opposing effects on the biophysical properties of the bacteria contribute to their membrane flexibility, which, on the one hand, is important to accommodate changing environments and, on the other hand, may inhibit the development of meaningful resistance to AMPs.