erase a base

Andrew Tai tai2 at scws14.harvard.edu
Fri Mar 11 14:21:30 EST 1994


In article <2ll8e2$904 at ysics.physics.sunysb.edu> mhollowa at epo.som.sunysb.edu writes:
>In article <hotan-080394162111 at pc10.hrfs.uiuc.edu> hotan@@uxa.cso.uiuc.edu (Douglas T.) writes:
>> Does anyone have any comments on the erase a base system? 
>
>Yes.
>ARRRRRGGGGGGHHHHHH!!!
>I've only tried it with the phosphorothiolate end protection and the 
>results were frustrating.  Out of, perhaps, 50 transformants one or two 
>were of plasmids whose ends had been protected from digestion.  The rest, 
>far as I could tell, were bi-directional digestions.  I expect that if I 
>had used a 3' overhang it would have worked much better.
>
	Strange that you had such an unfortunate experience. I was lucky
enough for my deletions to work just fine with the phosphorothioate end
protection. I did have a few bi-directional digestions, but not many
at all. BTW not all 3' overhangs work either. I seem to recall that ApaI, for
example, won't protect against ExoIII digestion.

	Andrew Tai
	tai2 at husc.harvard.edu




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