Best E. Coli?

Craig Morton craigm at
Wed Apr 21 09:57:58 EST 1993

Hi Bionetters,

	I am currently in the process of producing protein for subsequent NMR
analysis. Our clone is in a pGEX vector and we've had little problem growing
and expressing in L. broth. We have both XL1B and BL21 cell lines in use at the

	However, we now want to produce adequate amounts of 15N and 13C labelled
protein, requiring our bacteria to grow in minimal or defined media. They do so,
but with varying success..... some innoculations take and grow fine, others
only reach very low cell densities. (And, of course, when we use labelled
substrates we always get a low OD :-) ). We have no problem with induction,
the GST fusion protein is expressed to the same level as in L. broth. It's only
the cell density that is poor.

	I was wondering if anyone can point me towards a ref. or give advice 
about the _best_ E. coli strain for growing in minimal media. Alternatively,
does anyone have a favourite minimal/defined media recipe that gives good
growth? (We're using M9 with twice the glucose at the moment.)

Thanks in anticipation,


craigm at

Craig Morton                          ][
Research Assistant,                   ][ If you're not part of the solution,
Oxford Centre for Molecular Sciences, ][ You're part of the precipitate,
South Parks Road, Oxford.             ][

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