Rigidification of the Escherichia coli cytoplasm by the human antimicrobial peptide LL-37 revealed by superresolution fluorescence microscopy.

ABSTRACT: Superresolution, single-particle tracking reveals effects of the cationic antimicrobial peptide LL-37 on the Escherichia coli cytoplasm. Seconds after LL-37 penetrates the cytoplasmic membrane, the chromosomal DNA becomes rigidified on a length scale of ∼30 nm, evidenced by the loss of jiggling motion of specific DNA markers. The diffusive motion of a subset of ribosomes is also frozen. The mean diffusion coefficients of the DNA-binding protein HU and the nonendogenous protein Kaede decrease twofold. Roughly 10⁸ LL-37 copies flood the cell (mean concentration ∼90 mM). Much of the LL-37 remains bound within the cell after extensive rinsing with fresh growth medium. Growth never recovers. The results suggest that the high concentration of adsorbed polycationic peptides form

SUBMITTER: Zhu Y 

PROVIDER: S-EPMC6338858 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature