HomeFAQsIs there any variability in the distance of cutting from the MmeI cut site which is indicated as 20/18?
FAQ: Is there any variability in the distance of cutting from the MmeI cut site which is indicated as 20/18?
It is helpful to think of MmeI as placing the endonuclease at a (relatively) fixed distance from the recognition site, rather than the enzyme counting the bases between the recognition site and the position of cutting. The observation is that MmeI cuts predominately at 20/18 and 21/19, with approximately a 60%/40% ratio. There is also minor cutting at 19/17 (roughly a few percent). Individual sites can be cut at mostly one distance or can be cut at a mixture of distances (20/18 and 21/19); we believe this depends on the structure of the DNA between the recognition site and the cut site.