Cell surface display of recombinant proteins on Staphylococcus carnosus

Area of Science:

• Microbiology
• Biotechnology
• Immunology

Background:

• Surface display systems are crucial for various biotechnological applications, including vaccine development and diagnostics.
• Gram-positive bacteria offer unique advantages for surface display due to their cell wall structure.
• Previous systems have limitations in efficiency and versatility.

Purpose of the Study:

• To develop a novel and efficient expression system for the surface display of heterologous proteins on Staphylococcus carnosus.
• To demonstrate the feasibility of displaying functional proteins, including a malaria antigen, on the bacterial surface.
• To utilize fluorescence-activated cell sorting for analyzing surface-displayed receptors on gram-positive bacteria.

Main Methods:

• Utilized promoter and secretion signals from Staphylococcus hyicus lipase and cell wall-spanning regions of Staphylococcus aureus protein A.
• Constructed a fusion protein including a malaria blood stage antigen and a streptococcal protein G albumin-binding domain.
• Verified protein display using immunoblotting, immunogold staining, immunofluorescence, and fluorescence-activated cell sorting (FACS).

Main Results:

• Successfully achieved efficient surface display of an 80-amino-acid malaria antigen peptide on S. carnosus.
• Confirmed the presence of the malaria antigen, propeptide, and albumin-binding reporter protein on the bacterial surface.
• Demonstrated the first-time use of FACS for analyzing surface-displayed hybrid receptors on gram-positive bacteria.

Conclusions:

• The developed expression system enables robust surface display of heterologous proteins on Staphylococcus carnosus.
• This system holds potential for applications in diagnostics, vaccine development, and protein engineering.
• The use of FACS represents a significant advancement in analyzing surface display on gram-positive bacteria.