What's the highest MW recombinant protein that has been expressed in E. coli?

jlight at SICKKIDS.ON.CA jlight at SICKKIDS.ON.CA
Sun Nov 17 17:32:40 EST 1996


I'm attempting to express a human protein as a GST fusion in E. coli.  The
protein is about 165 kD, so with GST it would be about 195 kD.  When I
express the entire protein and analyze a whole cell lysate (i.e. without
attempting purification), I get a tiny amount of full-length protein, but I
also get about 12 partial products.  All of the partials have GST, since
they react with an anti-GST Ab.  I can express parts of the protein, up to
90 kD (120 kD if you include GST), without as many of the partial products
and with considerably more of the main product.  I'm assuming that the
large size of the protein is the problem, so that it's not stable in E.
coli.  I'd like to know if others have seen accounts of high MW foreign
proteins expressed in E. coli.  I'm considering using yeast as an
alternative, thinking that a eukaryotic expression system might help.
Thanks in advance for the help.





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