Bacterial display is an advanced service that links the function of a protein with the gene that encodes it. Creative Biolabs offers a unique bacterial display technology, for the identification of target-binding peptides.

Today, displaying of recombinant protein libraries are essential in many research areas, such as antibody screening, drug discovery, and protease substrate identification. Although phage display is still the most widely used method, alternative systems are available and are becoming increasingly popular.

Bacterial display (or bacteria display or bacterial surface display) is a protein engineering technique widely used for in vitro protein evolution. Libraries containing billions of diverse molecules polypeptides displayed on the surface of bacteria are screened using magnetic-activated cell sorting (MACS) or fluorescence-activated cell sorting (FACS). Peptide libraries can be constructed in Escherichia coli as insertions in extracellular proteins (such as pili or flagella subunits) or as insertions into outer membrane proteins for screening. The bacterial display system has been approved to be simple and efficient and has been applied extensively to find the affinity of a ligand for its target protein.

Figure 1. Identification of target-binding peptides from bacterial display peptide libraries (Getz et al. 2012)

With our extensive experience in bacterial display, we provide protein screening service by bacterial display. Our state-in-the-art technology enables the rapid isolation of target-specific proteins without the labor intensive screening. We provide several bacterial display scaffolds for library screening according to the sizes of passengers displayed, including OmpA, OmpX, FliTrx, FimH, CPX, Lpp (1-9) OmpA and nvasin (1-625).

The applications of bacterial display including but not limited to:

Epitope Mapping by Bacterial Display

Rapid and simple methods for the epitope characterization as well as the antibody cross-reactivity with other proteins are great needed to generate well-validated, protein-specific diagnostic, and therapeutic antibodies. Creative Biolabs has established state-of-the-art bacterial display platform for epitope mapping services. This strategy will likely provide a means to enhance the specificity of ligand panels, since specificity can be measured directly using FACS.

Cell-Binding Peptides Identification

The use of bacterial display provides a convenient means to identify ligands that mediate entry or invasion of target cells which can be further developed as drug targets. We identify cell-binding peptides by the help of FACS by co-expression of GFP to bacterial display libraries. We also developed a unique platform which enables quantitative screening via FACS for cell-specific ligands.

Protease Substrate Identification

The use of bacterial display provides a convenient means to identify peptide substrates for proteolytic enzymes. Creative Biolabs has established two-color bacterial display system termed cellular libraries of peptide substrates (CLiPS) for the identification of optimal peptide substrates of protease.

Protein-Binding Ligand Screening by Bacterial Display

The bacterial display is a well-established methodology for the discovery and optimization of peptides with binding functions. Our protein-binding ligand screening process allows real-time analysis of displayed peptide properties, including target-binding affinity, specificity, and peptide stability to proteases during screening. The ability to measure these properties enables efficient identification of peptides and allows direct evaluation of library population fitness.

Screening Antibody Fragments Library

Creative Biolabs has developed advanced anchored periplasmic expression (APEX) system to enable screening of antibody fragments, especially human scFv antibody. We have the ability to screen unique single-chain variable fragment (scFv) antibodies that have both high specificity and extremely high affinity, with K_d up to10^-12 for the target antigen.

Antibody Affinity Maturation by Bacterial Display

Affinity maturation is the process of improving the affinity of antibody for an antigen. Creative Biolabs has extensive experience in antibody affinity maturation. Utilizing our platform, clones with high-affinity to fluorescently-labeled hapten can be isolated with the principles of mutation and selection. In combination with FACS, antibody affinity maturation by bacterial display technology has become a powerful tool for rapid isolation and characterization of desirable mutants from libraries.

Live Bacterial Vaccine Delivery

We also provide live bacterial vaccine delivery vehicle development services through the surface display of foreign antigens on the bacterial surfaces. Our platform enables the construction of recombinant microorganisms capable of displaying heterologous proteins in different cellular compartments, improving the antigenic potential of vaccines against viruses, bacteria, parasites, and cancers.

Reference

1. Getz J A, Schoep T D, and Daugherty P S (2012) “Peptide discovery using bacterial display and flow cytometry.” Methods Enzymol 503:75-97. doi: 10.1016/B978-0-12-396962-0.00004-5.

All listed services and products are For Research Use Only. Do Not use in any diagnostic or therapeutic applications.