Heat stable E.coli protein

Duncan Clark Duncan at genesys.demon.co.uk
Wed Jan 12 14:25:33 EST 1994


In article <1994Jan12.124632.444 at nrcnet0.nrc.ca> phi at nrcbsa.bio.nrc.ca writes:

>Could the 70 kDa band correspond to the heat shock protein / molecular
>chaperone dnaK?
>

Hi Folks,

I have had another reply suggesting the same. Whatever it is it is probably
constitutes 99% of the surviving E.coli proteins and the protein band is big!
E.coli W (ATCC 9637 - I looked it up this time!) has a lot more than say
TOP10F' or other MM294 derivatives but less of other heat stable proteins. You
pays your money and takes your choice. This strain which is used as the normal
commercial host strain for ExoIII production was reported in this application 
(somewhere in a Methods in Enzymology - I will post the ref when I find it 
amongst the paperwork) to grow to an OD of 75 in a media similar to terrific 
broth without too much in the way of fermentor control. In baffled shake flasks
I can get up to an OD600 of 25 under expression with IPTG. It is even better
without expression. Other normal(?) strains such as DH5 etc get up to around 
OD600 of 8 in similar conditions. 

Duncan 
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Duncan Clark                        | Internet:    duncan at genesys.demon.co.uk
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