Artifact in plasmid preps

[Mark R. Miglarese]

It sounds like you have what we call "the ghost band".  It comes and 
goes with minipreps, but we usually don't see it in lg. scale (2xCsCl) 
preps.  It's permanently denatured DNA and wont transform, cut or mess 
up your ligations.  Having said that, I still don't like it hanging 
around.  It's your call....best wishes.

Mark R. Miglarese, Ph.D.
Cancer Research
Pfizer Central Research
Box 372                        
Eastern Point Road              
Groton, CT 06340
                
Phone: (860) 441-8478
FAX:   (860) 441-1290
Email: miglaresemr at pfizer.com