ligation transformation.......which chemically competent cells are the best? - (Feb/27/2008 )

Hi everybody------
I was just wondering what chemically competent cells (what strain and company) do you think are the most efficient for heat shock transformation of a ligation----when I clone, my vector+insert size varies from 6.0 KB upwards to a little over 10 KB depending on what vector/insert I'm using. I'm so confused on which to use because there are so many companies and cell types claiming they are the best.
thanks---I really appreciate your help
Lisa

Hi Lisa,

You'll be even more confused when you see other people's replies. I think everybody has their own favourite company and once it works for them, they stick to it. This is what I do, too, so I can only share my experience.

I use Stratagene XL-1 Blue and XL-10 competent cell for transformation (maybe also because we have quick access to them).
I've ligated constructs up to 7.3 kb and I use the XL-1 Blue in most cases, in easy, non-sensitive ones. I used XL-10 to generate constructs for further bacterial protein expression.

I know this is not much help, but I'm sure the more experienced ones will reply soon and give you more details.

Krisztina

Yeah, Krisztina's totally right with this one Lisa. They're all one in the same really, pretty much just different versions of the same E. coli K12 strain so they all pretty much do the same thing. Some have slightly different genotypes - eg. methylation negative and recombination deficient for unstable clones - but they all do the same job.