FAQ: What is the difference between EnGen® Spy Cas9 Nickase (NEB #M0650) and EnGen Spy Cas9 NLS (NEB #M0646)?

EnGen Spy Cas9 Nickase contains a single point mutation (D10A) that inactivates the RuvC nuclease domain, but leaves the HNH nuclease domain intact, rendering the enzyme a nickase. EnGen Spy Cas9 NLS has both nuclease domains active and is able to cleave both strands of dsDNA.