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dh5 alpha competent cells? - (Apr/15/2010 )

Are DH5 alpha competent cells dam+ or dam-, and to be clear...if they are dam+ does that mean that they methylate DNA, and that restriction enzymes that are dam sensitive would NOT digest DNA isolated from DH5 alpha cells?

I'm trying to digest a plasmid isolated from DH5 alpha cells with BsaBI (NEB) but it's not cutting....



Yes, DH5a is dam+ (see and yes it blocks your BsaBI digestion. You have to subclone vector into dam- cells.


If you're in the US, NEB will send you E. coli K12 ER2925 (dam- , dcm-) for free with any order... Need some more BsaBI?