Sortases are a family of membrane–anchored transpeptidases expressed by Gram–positive bacteria. Sortase A catalyzes the cleavage of C-terminal recognition motif (LPXTG) of multiple structurally unrelated proteins followed by formation of an amide bond with the peptidoglycan layer of the bacteria. Since Sortases are widely distributed among a variety of bacterial pathogens and required for virulence, Sortases represent a promising therapeutic target for the development of novel anti-infective agents. In addition, Sortase A can be used as a biotechnology tool for a variety of protein modifications and immobilization by sortase-mediated protein ligation.
Sortase A from Staphylcoccus aureus was expressed in E. coli expression system with a N-terminal His tag. It is comprised of 26-206 amino acids and its MW is 21.7-kDa. The activity of Sortase A can be measured in a FRET-based enzymatic assay