The CRISPR-associated protein Cas12a (previously known as Cpf1), which is an endonuclease from the type V-A CRISPR system, has been applied in both in vivo genome editing and in vitro DNA assembly. 1 , 2 , 3 Cas12a is guided by a single CRISPR RNA (crRNA) with a T-rich protospacer adjacent motif (PA...