blunt end ligation and peg 8000

leclair leclair at mpiz-koeln.mpg.de
Wed Jul 30 04:24:18 EST 1997


Hi, all,

I am trying to perform a quite tricky blunt end adapter ligation to
double stranded cDNA molecules. Unfortunately the ligation efficiency
following the protocol is not good enough. The amount of the leftover
sample does not allow me to increase the concentration of the cDNA but I
could increase the amount of adaptors. 
When I looked up blunt ended ligation in several molecular cloning books
I found that the addition of PEG 8000 is said to improve ligation
efficiency. Alas, all three books gave different concentrations for the
PEG 8000 ranging from 5% to 15%. They also gave different factors of
improvement ranging from 3 fold to 1000 fold.

Does anybody have experience with the addition of PEG 8000 to blunt end
ligation reactions or could anybody point out other ways of improving
it?

Thanks a lot					Frank



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