Heterologous Expression and Purification of a CRISPR-Cas9-Based Adenine Base Editor.

CRISPR-cas9-guided adenine base editors (ABEs) site-specifically convert the A-T base pair to G-C base pair in genomic DNA. The intracellular delivery of ABE proteins preassembled with guide RNAs (gRNAs) has shown greatly reduced off-target effects compared with that of plasmids or viral vectors containing ABE and gRNA-encoding sequences. For efficient gene editing by the ribonucleoprotein delivery method, the ABE-gRNA complexes need to be prepared in high purity and quantity. Here we describe the expression and purification procedure of ABEmax, one of high-efficiency ABE versions.