Plasmid size limitation on E. Coli Transformation?

Paul N Hengen pnh at fcsparc6.ncifcrf.gov
Tue Aug 23 10:28:30 EST 1994


brianc4208 at aol.com (BrianC4208) says:

> I've been having a problem transforming DH5Alpha cells with a ligation
> I've been trying.  I think the problem might be that the plasmid is just
> too darn big, somewhere < 15 KB. 

This should not be a problem. Try leaving the cells with DNA on ice for a long
time (~ 1 hr.) without being disturbed, and express at 37 C for a long time
(maybe 3 times as long as normal = 1.5 to 2 hrs.). Then, plate as many cells as
you can on selective media.

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* Paul N. Hengen, Ph.D.                           /--------------------------/*
* National Cancer Institute                       |Internet: pnh at ncifcrf.gov |*
* Laboratory of Mathematical Biology              |   Phone: (301) 846-5581  |*
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