SexA I: digestion problems

Lena Polovnikova elena at
Fri Oct 13 11:45:37 EST 1995

In article <malexeyev-1210952146510001 at>,
malexeyev at (M. Alexeyev) wrote:

> Lena,
> Recognition sequence for SexAI is ACCWGGT. It overlaps CCWGG site that is
> being methylated by E. coli dcm methylase. PCR fragment is not methylated,
> however, it could be not clean enough to be digested completely. Is it
> possible that your other plasmid has been isolated from dcm- strain? I
> beleive NEB provides dcm- strain free of charge.
> Good luck,
> M.Alexeyev
Thanks for your help! I beleive there is a very good chance that might be
the reason! I isolated my plasmid from XL1-blue, which, I beleive is not
dcm-, the other plasmid I was given by someone else, so I don't even know
which strain it comes from.

Lena Polovnikova
Purdue University BMB Program
elena at

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