Thanks for your answer Duncan,
I've found on the net a realy good site listing tons of dam- dcm- and
mut- E. coli K12 strains :
http://users.umassmed.edu/martin.marinus/dstrains.html
GM2929 strain will be my choice, I've asked for it @ E. coli Genetic Stock
Center (http://cgsc.biology.yale.edu)
However, it is nor RecA- neither RecBC- but RecF-, and I don't know the
effect of RecF inactivation compared to RecA or RecBC... Does anyone here
know ?
For the Dcm methylation system in E. coli, i'm sure it exists. Here is the
copy of a catalog information about it :
"Most laboratories strains of E. coli contain three site specific DNA
methylases. The methylase encoded by the dam gene [...].The Dcm methylase
(encoded by the dcm gene; referred to as the Mec methylase in earlier
references) methylates the internal cytosine residues in the sequence CCAGG
and CCTGG at the C5 position (see refs). The EcoKI methylase, [..."
Marinus, M.G. & Morris N.R. (1973) J. Bacteriol.,114, 1143-1150
May, M.S. & Hattman, S (1975) J. Bacteriol., 123, 768-770
I have to say that I've never read this references but I give it to you in
case you find it interesting. I guess we misunderstood & you were talking
about another dcm gene (since this tree letter name allows sometimes
different enzymes/genes to have the same name).
Regards,
Eric Dufour
