Candidatus Falsirhodobacter halotolerans DnaE split intein (Cfa split intein) (Cfa split intein)

The Cfa split intein is a highly efficient protein-splicing element derived from the DnaE polymerase of the bacterium Candidatus Falsirhodobacter halotolerans (Stevens, A. J., et al., 2017, JACS). It is composed of two separate polypeptides, the N-terminal (CfaN) and C-terminal (CfaC) fragments, which possess a high affinity for one another and undergo spontaneous reassembly. Once assembled, the intein catalyzes its own excision while simultaneously joining the flanking protein sequences, known as exteins, with a native peptide bond through a process called protein trans-splicing (PTS). This intein is particularly valued in biotechnology due to its exceptional splicing speed, high yields, and robustness across various temperatures and buffer conditions. It is frequently employed in synthetic biology and gene therapy to circumvent size limits of delivery vectors, such as Adeno-associated viruses (AAV), by splitting large therapeutic proteins like Cas9 into two parts that reconstitute functionally within the target cell (Li, J., et al., 2021, Communications Biology). While not a traditional drug target, its role as a molecular tool is critical for developing next-generation biologics and precision medicines.

Other names

CfaN/CfaCCfa DnaE inteinFalsirhodobacter halotolerans split inteinCfa split intein N- and C-fragments

Protein trans-splicing (PTS) involving four nucleophilic displacement steps to ligate flanking exteins.