Technologies for Proteome-Wide Discovery of Extracellular Host-Pathogen Interactions

Martinez-Martin, Nadia

In addition to these encouraging technologies, the generation of phagemic libraries has also represented an important tool for deciphering PPIs, in this case between particular binding partners and the whole genome of specific pathogens [146] [147] [148] . Typically, pathogen-encoded molecules are expressed as fusions with phage envelope proteins, a method known as phage display that has been widely exploited to identify peptides with specific binding properties. For example, Beckmann and colleagues built a phage display library to identify novel group B streptococci proteins capable of mediating adherence to fibronectin, a major component of the extracellular matrix often exploited for colonization of the host [51] . From this analysis, the authors identified 19 genes with homology to known bacterial adhesin proteins, genes involved in virulence, transport, or metabolic processes, along with genes with uncharacterized functions. Interestingly, one of these genes showed significant homology with the ScpB protein, a peptidase found in other streptococci that inactivates the member of the human complement system C5a, suggesting that this bacterial molecule acts as a bifunctional protein, similarly to other examples of multifunctional proteins discussed above [51] .