A plasmid mobility question. - (Dec/15/2006 )

I have been recently testing the intactness of my plasmids,
since I have trouble in transfection efficiency.

I knew that the supercoiled form of plasmid move faster than the linear form.

In my assay, I found that the supercoiled form did move faster at first,
but later on, the linear form just cought up with it and finally overtook it.

Does anyone understand why?

Picture


I used a simple assay:

1. purified plasmid
2. purified plasmid cut by a restriction enzyme
3. as the condition of 2, but without restriction enzyme
(# sample 2 & 3 are both in a condition containing BSA, NEB buffer 2)

Samples were running on 8% gel.

0.8% gel, sorry.

i cant understand ur picture. why u send a portion of the pic?? plz send the whole gel pic. didnt u use any marker ???

Here are the lanes with markers~
picture