Pathogenic, versatile and tunable activity of sortase, a transpeptidation machine

Bacterial sortases are a very interesting but also challenging subject of study. The whole family consists of six dissimilar groups and each group consists of hundreds of different members. Despite general knowledge about sortases, coming mostly from studies performed on Staphylococcus aureus sortase A (SrtA), every member of the sortase family needs to be examined separately with respect to specificity and activity. Additionally, sortases are a group of enzymes with two sides to them, as they can be used as a target for new antibiotic strategies and as a tool for biotechnological applications. Such abilities leave the door wide open to a great range of studies that can be performed on this enzyme; work performed in this thesis focused on SrtA from two strains of Gram-positive bacteria, Staphylococcus aureus and Streptococcus pyogenes. I examined the potential of SrtA as a target for antimicrobial drugs and as a tool for site-specific conjugations. While exploring and optimizing features of SrtA, I made use of different protein engineering techniques. Additionally, I looked at the recent advances in high-throughput screening systems and applied one of these methods to the evolution of SrtA from S. aureus