Quantitative Analysis of Bacillus pumilus Serine Proteinases in Recombinant Bacillus Strains

A comparative study of the expression of B. pumilus extracellular serine proteinases (subtilisin-like proteinase and glutamyl endopeptidase) under the control of different promoters and signal peptides based on the LIKE expression system in various B. subtilis recipient strains was carried out using mass spectral analysis in the monitoring of multiple reactions (MRM) mode. The maximum expression of the subtilisin-like proteinase was established under the control of a simulated signal peptide (SPAsp) and an inducible promoter of the P-LiaI-LIKE expression system in the protease-deficient strain B. subtilis 20-36; the amount of secreted protein was 1.6 mu g/mu L of the culture liquid. The optimal expression of glutamyl endopeptidase was established under the control of the signal peptide of the Bacillus megaterium glycoside hydrolase gene (SPYngk) and the inducible promoter P-LiaI in the protease-deficient strain B. subtilis 20-36, the maximum amount of protein was 0.06 mu g/mu L. It was concluded that selection of all components of the expression system for individual secreted proteins is of importance, including the selection of the optimal signal peptide.

Automated summary

A study comparing the expression of B. pumilus extracellular serine proteinases under different promoters and signal peptides revealed that the selection of optimal signal peptides is crucial for individual secreted proteins.