No protein expression in pKK223-3 vector in JM105 - (Apr/15/2008 )

I tried to induce my protein in pKK223-3 vector in JM 105 host and got nothing. can any one plz tell me if JM 105 is a suitable host for expression studies?

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PKK223 & JM105 are old skool expression system, are you in a microbiology lab? Should work fine though. How old are your competent cells? Make sure JM105s are still have the F' which
carries the lacIq repressor gene, you can do this by passaging the cells through M9 + glucose. Alternatively buy or make some fresh BL21 cells. Life is too short to mess around with old cells.

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hi drewaight,

Thanx for your words n I think I will try my luck with BL21 cells.

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Try to use BL21 DE3 for better expression. I dont usually use JM series for expression. I think the JM series has additional plasmid? I cant recall.
Is your protein toxic? If so use BL21 Plyss.

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