AUTHOR=Tran Buu Minh , Prabha Haritha , Iyer Aditya , O’Byrne Conor , Abee Tjakko , Poolman Bert 

TITLE=Measurement of Protein Mobility in Listeria monocytogenes Reveals a Unique Tolerance to Osmotic Stress and Temperature Dependence of Diffusion

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.640149

DOI=10.3389/fmicb.2021.640149

ISSN=1664-302X

ABSTRACT=<p>Protein mobility in the cytoplasm is essential for cellular functions, and slow diffusion may limit the rates of biochemical reactions in the living cell. Here, we determined the apparent lateral diffusion coefficient (<italic>D</italic><sub><italic>L</italic></sub>) of GFP in <italic>Listeria monocytogenes</italic> as a function of osmotic stress, temperature, and media composition. We find that <italic>D</italic><sub><italic>L</italic></sub> is much less affected by hyperosmotic stress in <italic>L. monocytogenes</italic> than under similar conditions in <italic>Lactococcus lactis</italic> and <italic>Escherichia coli</italic>. We find a temperature optimum for protein diffusion in <italic>L. monocytogenes</italic> at 30°C, which deviates from predicted trends from the generalized Stokes-Einstein equation under dilute conditions and suggests that the structure of the cytoplasm and macromolecular crowding vary as a function of temperature. The turgor pressure of <italic>L. monocytogenes</italic> is comparable to other Gram-positive bacteria like <italic>Bacillus subtilis</italic> and <italic>L. lactis</italic> but higher in a knockout strain lacking the stress-inducible sigma factor SigB. We discuss these findings in the context of how <italic>L. monocytogenes</italic> survives during environmental transmission and interaction with the human host.</p>