esb (microb at esb.utexas.edu) wrote:
: entire Bovine Pancreatic Trypsin Inhibitor cDNA contains pre sequence (for
: secretion) pro sequence (these two are all processed out in mature protein)
: and mature sequence.
: i tried to express mature BPTI and pro+mature BPTI in e.coli periplasm, and
: found out that pro+mature BPTI express much more poorly then mature BPTI
: only. i guess the pro sequence has something to do with it. but i could not
: see any sign of degradation by western.
: so my question is: anyone remember any reference about pro sequence
: affecting protein expression?
: thanks in advance.
Most likely to codon usage problem. Large number of rare codons
especially if it appear in cluster, as is likely with your pro
sequence, will tends to decrease yield. Associate with this is the idea
of 'hungry codon', i.e. when large number of the same codon are
present, even if it is not very rare, can lead to low expression level.
I have some reference about this somewhere (though not necessary about
proline), e-mail me and I'll see if I can dig them up.
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