Golden Gate Assembly is a one-tube efficient cloning method based on Type IIS restriction enzymes that cleave outside their recognition sites and leave 3 or 4-base overhangs. BsaI is the most commonly used Type IIS enzyme for Golden Gate Assembly. NEB also offers an engineered high-fidelity version of this enzyme, BsaI-HF®v2, which has the added benefit of being Time-Saver™ qualified (can digest DNA in 5-15 mins or overnight without degradation to DNA) and exhibits dramatically reduced star activity. Other Type IIS enzymes used in Golden Gate Assembly include BsmBI-v2/Esp3I, BbsI/BbsI-HF, PaqCI (AarI isoschizomer with 7 bp recognition sequence), and SapI/BspQI (with 7bp recognition sequence and 3bp overhangs).
Type IIS restriction enzymes have both recognition and binding sites, but cut downstream of the recognition site, creating 4-base overhangs ideal for re-assembly. View a list of TypeIIS enzymes.