# Development of Efficient Expression Systems for Bacteriolytic Proteases L1 and L5 of Lysobacter capsici XL1

## TL;DR

Scientists developed efficient systems to produce two enzymes from Lysobacter capsici that can break down bacterial cell walls, which could lead to new antimicrobial drugs.

## Contribution

The study introduces homologous expression systems for L1 and L5 proteases with significantly higher yields compared to previous methods.

## Key findings

- Expression strains L. capsici PT5–alpA and PT5–alpB produced 4 and 137 times more enzymes than the wild-type strain.
- Enzyme yields reached 35.48 mg/L for L1 and 57.11 mg/L for L5 in a 10-L bioreactor.
- Homologous systems outperformed previous heterologous methods in yield and simplicity.

## Abstract

Secreted bacteriolytic proteases L1 and L5 of the Gram-negative bacterium Lysobacter capsici XL hydrolyze peptide bridges in bacterial peptidoglycans. Such specificity of action determines the prospects of these enzymes for medicine with the view of creating new antimicrobial drugs to combat antibiotic-resistant strains of pathogens. This research concerns the development of successful expression systems for producing active enzymes L1 and L5 in sufficient amounts for comprehensive studies. Based on L. capsici XL strains with deletions in the alpA (enzyme L1) and alpB (enzyme L5) genes and the constructed expression vectors pBBR1-MCS5 PT5–alpA and pBBR1-MCS5 PT5–alpB, we obtained expression strains L. capsici PT5–alpA and L. capsici PT5–alpB, respectively. The yields of enzymes L1 and L5 in the developed strains increased by 4 and 137 times, respectively, as compared to the wild-type strain. The cultivation of the expression strains was successfully scaled up under non-selective conditions in a 10-L bioreactor. After fermentation, the yields of enzymes L1 and L5 were 35.48 mg/L and 57.11 mg/L, respectively. The developed homologous expression systems of bacteriolytic proteases L1 and L5 have biotechnological value as compared to those obtained by us earlier based on heterologous expression systems, which have lower yields and labor-intensive purification schemes.