A restricted or AT-rich target region for genome editing experiments may lack a PAM NGG motif recognized by S. pyogenes Cas9. The Acidaminococcus sp. BV3LC Cpf1 enzyme uses a PAM site of TTTV (i.e., TTTA, TTTC, TTTG). It is therefore especially useful for targeting AT-rich regions. Read about this and other alternatives when targeting sequences with few or no NGG sites.