difference between DH5alpha and lamda pair DH5alpha? - (Oct/16/2006 )

Hi, does anybody know the difference between normal DH5a and lamda-pair DH5a?

thanks...

Paula

The lamda pir strain contains a phage that allows for production of a pir protein. Plasmids that have an R6K origin of replication can only replicate in pir strains because they need the pir protein. These plasmids are used as suicide vectors which means they can be trasferred into a strain (usually by conjugation) but they won't replicate. In this way you can make mutants through homologous recombination. Such plasmids include, pGP704 or its derivative pCVD442.

thank so much for the note--now I can understand why some of my labmates use DH5alpha competent cells for the transformation of R6K-replicon plasmid....

Paula