LL-37 is a secretory peptide that has antimicrobial
activity. Ribonuclease 1 (RNase 1) is a secretory enzyme that is
not cytotoxic. Authors Chelcie Eller and Ron Raines find that human LL-37 and human RNase 1 can act synergistically to kill Gram-negative bacterial cells.

In the presence of nontoxic concentrations of LL-37, RNase 1 is toxic to Escherichia coli cells at picomolar levels. Using wild-type RNase 1 and an inactive variant labeled with a fluorophore, they observe the adherence of RNase 1 to E. coli cells and its cellular entry in the presence of LL-37.

These data suggest a natural means of modulating the human microbiome via the cooperation of an endogenous peptide (37 residues) and small enzyme (128 residues).

Title:
Antimicrobial Synergy of a Ribonuclease and a Peptide Secreted by Human Cells
Authors:
Chelcie H. Eller and Ronald T. Raines
Citation:
ACS Infect. Dis. 2020, 6, 3083−3088
URL:
https://pubs.acs.org/doi/10.1021/acsinfecdis.0c00594