High-throughput comparative and functional genomic analysis of type IV pilus (Tfp) localised adhesins in the opportunistic human pathogen Streptococcc

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Tfp are key virulence factors in many human bacterial pathogens thta cause millions ofdeaths each year worldwide. A better understanding of Tfp biology is highly desirable as itwill be crucial for developing new prevention and therapy methods. Tfp are key for hostcolonisation as they mediate attachment fo bacteria to host cells and surfaces.Unfortunately, the molecular mechanisms of Tfp-mediated adhesion are poorlyunderstood, which hinders the design of new treatments. This project stems from on ourrecent discovery of subunits that are likely to play a direct role in adhesion in the Tfp ofthe opportunistic human pathogen S. sanguinis, which causes infective endocarditis a lifethreateningcondition. During this project, we will use a state-of-the-art multi-disciplinaryapproach combining high-throughput genomics, molecular genetics, protein biochemistryand structural biology to characterise in detail these two newly discovered adhesins namedPilB and PilC. In brief, since a preliminary comparative genomic analysis on the fewpublicly available S. sanguinis genomes revealed some sequence variability in PilB andPilC, which might have important functional consequences, a large collection of clinicalisolates of S. sanguinis will be sequenced to determine the degree of variability of thesetwo adhesins and see if there is a correlation with clinical symptoms. Then, usingmolecular genetics, the functional consequences of these sequence variations will beanalysed in vivo. Finally, representative variant proteins will be purified, analysedfunctionally in vitro and submitted to structural analysis. This is expected to give anuprecedented understanding of Tfp-mediated adhesion and could be the first step towardsthe design of new drugs interfering with Tfp-mediated colonisation in important humanbacterial pathogens.