Phage display as a novel screening method to identify extracellular proteins

Area of Science:

• Microbiology
• Molecular Biology
• Bacteriology

Background:

• Extracellular proteins play crucial roles in bacterial cell functions and pathogenesis, acting as potential virulence factors.
• Identifying genes encoding these proteins is essential for understanding bacterial mechanisms and developing therapeutic strategies.
• Current methods for identifying extracellular protein genes can be limiting.

Purpose of the Study:

• To develop and present a novel method for identifying genes encoding extracellular proteins in bacterial genomes.
• To utilize phage display technology for efficient screening of bacterial genetic libraries.
• To isolate genes responsible for secreted and transmembrane proteins in pathogenic bacteria.

Main Methods:

• Construction of a novel gene III-based phagemid vector, pG3DSS, lacking the native signal sequence.
• Random fragmentation of Staphylococcus aureus chromosomal DNA and insertion into the pG3DSS vector.
• Phage display selection using an E-tag epitope for isolation of phagemids encoding signal sequences and fusion proteins.

Main Results:

• The developed method successfully identified genes encoding extracellular proteins.
• Isolated genes included those for adhesins, enzymes, and transport proteins from Staphylococcus aureus.
• The system specifically selects for phagemids containing inserts with functional signal sequences.

Conclusions:

• The presented phage display method is effective for identifying genes encoding secreted and transmembrane proteins in bacteria.
• This approach provides a valuable tool for the study of bacterial virulence factors and essential proteins.
• The pG3DSS vector and selection strategy offer a robust platform for genomic analysis of extracellular proteins.