Large plasmid cloning

[D.K.]

In article <4097e869$1_1 at mk-nntp-2.news.uk.tiscali.com>, "N. Horner" <horner1978 at yahoo.co.uk> wrote:
>I've been attempting some cloning since January with no luck. It turns out
>that the Ligase I was using was inactive (Promega). You might want to check
>yours by ligating  Lambda DNA/Hind III fragments and then checking on a gel.

The fact that one has to use everything "Promega" at twice higher 
concentrations aside, the most common problem with it's ligase 
is bad/hydrolysed ATP in ligase buffer. Adding extra 2 mM ATP
usually solves the problem. 

DK