HELP: Ligation

[Chaitanya Athale]

Dear Users,
  I have a problem with cloning a PCR amplified fragment into a commercial
expression vector. The PCR amplicon has the same Restr Enz site and the
plasmid only one site ofr it. i end digest the plasmid and fragment,
dephosphorylate, separate on a gel, and purify the gel bands (kit) and then
use the fragments for ligation (20h, 4/ 16 deg C). Once I een saw a
presumably ligated fragment, but no transformed colonies of XL1 Blue.
  suggestions, tips, tricks etc?
Thanx,
Chaitanya  
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Chaitanya A. Athale,
Dept. of Chemistry and Biochemistry,
Universität Bern,
Freiestrasse 3,
CH-3012 Berne,
Switzerland.

Tel.:  ++41/ (0) 31/ 631 4337
Fax: ++41/ (0)31/ 631 4887
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