BL21 Codon-plus

Mizar molla-remove- at
Thu Nov 9 06:51:15 EST 2000

Hi everyone,
After many efforts, we are not still able to express our recombinant
human protein in E. coli. so we are thinking to switch to codon-plus
Someone tried the BL21 codon plus (DE3) strain from Stratagene?

Another question: there are 2 strains with different tRNAs:
both have the AGA/AGG tRNA but
RP posses the CCC tRNA
RIL posses the AUA and CUA tRNAs

In my gene I have 6 CCC codons and 4 AUA + 3 CUA codons;
do you think it's better to overcome the 6CCC problem (RP strain)
or the 4AUA+3CUA problem?
In other words are more problematic 6 unusals codons of the
same type or 7 unusal codons of different types?

Thank you for your attention.


Gianluca Molla Ph.D.
Dept. of Structural and Functional Biology, University of Insubria
via J.H. Dunant 3, 21100 Varese (ITALY), mail:
gianluca.molla at
Tel. ++39-0332-421414 Fax. ++39-0332-421500

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