Optimal Electroporation settings for JM109

[Silke Beismann]

Tam Anh Le wrote:
> 
> Hello all
>     I have always used heat shock as a methods of transforming bacterial
> cell with my desired plasmid, however my supervisor has told me that
> electroporation is a more effective than heat shock. To that extend I want
> to try this method of transformation, however I do not have the information
> regarding the optimal setting host strain JM109, I am hoping someone out has
> this information and could share it with me.
> 
> -Many thanks
> 
> --
> Tam Anh Le
> Clinical Neuroscience
> St Vincent Hospital Melbourne.


Hi Tam Anh,
this is the way I carry out the electroporation:
fill 50 microliter electrocompetent E. colis (e. g. JM109)into a
procooled electroporation cuvette, add 2-4 microliter desalted
(dialysed) ligation product and mix gently. Insert into a gene pulser
(e.g. from BioRAD) and then:1 pulse at 200 Ohm, 25 microF, 2.5 kV.
If the DNA is readily desalted you will hear a buzzing sound- otherwise
a big bang! You can still try to propagate the survivers...
Add 1 ml of SOC immediately after the pulse and cure for 1 h at 37
degree. Plate 100 to 300 microliter on plates with appropriate medium
(e.g. with antibiotics). Thats it!

SOC: 	2 percent trypton
	0.5 percent yeast extract
	10 mM NaCL
	2.5 mM KCl#	
	20 mM MgCl2
	autoclave
then:	add 20 mM glucose.

Good look,
Silke