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Another band after plasmid purificaiton - ran the plasmid DNA on a gel (Oct/21/2009 )

Dear all,
I have got a problem about plasmid purificaiton. After the plasmid purificaiton, I ran plasmid DNA on a gel , but there is an another band before super colied plasmid .
I do not know what happened . Do you have any suggestions? Thanks a lot!
Attached Image

-tantao-

I'm assuming it is uncut plasmid? In which case it is probably your plasmid in another conformational state, like relaxed circular.......which runs slower than the supercoiled.

-leelee-

leelee on Oct 22 2009, 02:04 PM said:

I'm assuming it is uncut plasmid? In which case it is probably your plasmid in another conformational state, like relaxed circular.......which runs slower than the supercoiled.


Dear leelee,
maybe I do not explain this problem clearly. so I edit my photo, and the stranger band, I have marked it with asterisk.. I do not digest the plasmid with any enzyme, there should be no band! so I do not know what happened!

-tantao-