LbCas12a

So far, 6 types and more than 20 subtypes of CRISPR-Cas systems have been discovered. Among them, CRISPR-Cas12a is the second type (type V) CRISPR-Cas system for editing mammalian genomes. Cas12a has unique functions that can complement the CRISPR-Cas9 system. The Cas12a (Cpf1) protein has a RuvC endonuclease domain similar to Cas9.

In addition, Cpf1 does not have an HNH endonuclease domain, and the N-terminus of Cas12a does not have the α-helical recognition lobe of Cas9. The DNA double-strand break after Cas12a performs shearing introduces a sticky end with 4 or 5 nucleotide protrusions.  

Studies have shown that the binding of LbCas12a-crRNA complex with complementary single-stranded DNA or double-stranded DNA releases strong non-specific ssDNA trans-cleavage activity, which enables Cas 12a to be used as a new type of gene detection and imaging tool.