ENgineering of an intein enzyme

Background

Inteins or internal proteins are enzymes that catalyze the splicing of the polypeptide chains (external proteins or exteins) at their N-and C-terminus (see the figure above). These enzymes have found immense biotechnological applications (Wood 2014) such as self-cleaving affinity tags for protein purification, ligation of peptide chains, synthesis of cyclic peptides and circular proteins, site-specific labeling of proteins, and biosensors for detecting protein-protein interactions, protein-DNA interaction, redox states and protease activity.

In our lab, we have identified a new intein enzyme from Spirulina platensis and thoroughly characterized its function and structure (Boral 2020). This intein, named Spl DnaX mini-intein, is one of the smallest, fastest and stable intein enzymes discovered till date, and hence, ideal for protein engineering. We have solved its structure by solution NMR spectroscopy (PDB code: 7CFV).