Cas12a, also referred to as Cpf1, is a type V CRISPR-Cas nuclease. It was originally discovered in Acidaminococcus and Lachnospiraceae bacterium as an adaptive immune response system for bacteria. Similar to Cas9, Cas12a also induces a double strand break but at a more efficient rate (Zetsche, B. et al, 2015, PMID: 26422227). However, Cas12a creates a staggered double-stranded cut in the target DNA, which can be useful for homology directed repair pathways.
Cas12a’s PAM sites are AT-rich making it a useful tool to edit AT-rich genomes and enabling targeting of genomic regions that lack SpCas9 PAM sites (Kim, H., et al, 2017, PMID: 27992409). Cas12a is a much smaller protein than SpCas9 and does not require a tracrRNA, which is why its guide RNA is much shorter (40-44 nucleotides long).
When designing sgRNAs for Cas12a it is crucial to place the scaffold at the 5’ end and the sequence-specific guide on the 3’ end [5' - Scaffold + Guide - 3'] to allow the ribonucleoprotein (RNP) complex to form properly. (Li, B. et al. 2017, PMID: 28840077). Do not include the PAM sequence.
You can order Cas12a synthetic gRNAs from Synthego as an Advanced RNA product. You will need to enter both the scaffold for the specific Cas12a variant you are using as well as the target-specific guide sequence. You can order Cas12a nuclease here.