The catalytic cysteine residue is found in this cleft and accepts subsequent binding of a nucleophilic agent.
[4] Sortase A has been widely used as an in vitro tool to post-translationally modify proteins at the N- and C-termini with an appended label.
Upon cleavage of the LPXTG motif, Sortase forms a thioester intermediate with the engineered molecule.
Finally, both N and C-termini of proteins can be labeled by using Sortases of different substrate specificity.
For example, Sortase A from streptococcus pyogenes, recognizes and cleaves the LPXTA motif and accepts Ala-based nucleophiles.