poor expression of foreign proteins

Vincenzo Nardi-Dei vinz at PCLSP2.KUICR.KYOTO-U.AC.JP
Wed Feb 9 01:39:30 EST 1994

I have recently cloned in E. coli an hydrolase from Pseudomonas
putida, which M.W. is 35,000. The host is XL1 Blue provided
by Stratagene and the vector is pUC118. The inserted gene is
about 1500 bp and seems constitutively expressed at around
the 10% of the total crude extract, but a lot of the protein is found
as inclusion bodies.
Moreover, in LB medium, 37 C and reciprocal shaking 200 rpm,
the recombinant cells take 48 (!) hours to reach
full growth, both in presence and in absence of IPTG.

This is not the first time I got inclusion bodies and poor growth
using XL1 Blue and also some collegues of mine have
experienced the same problem with this vector.

Does anybody can kindly suggest me which strain of E. coli is
the most suitable for high expression of foreign proteins in
such conditions?

Thank you very much indeed,

Vincenzo Nardi-Dei

Institute for Chemical Research
Kyoto University 611

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