pET-26b pelB Leader?

Michael Benedik bchs1b at Elroy.UH.EDU
Fri Apr 29 12:02:59 EST 1994

In article <CoyCBr.88u at>, pdurham_pt4 at (Patrick G. Durham) writes:
>Hi there, 
>I have the pET-26b vector from Novagen and I was wondering the
>advantages/disadvantages of the leader sequence pelB that is put in after the
>RBS.  According to Novagen, "the pelB leaders are designed to direct the target
>protein to the periplasm, which may promote proper folding and protect against
>proteolytic breakdown."  I'm not specifically looking for this kind of action
>but maybe it is generally beneficial for most proteins.  
>Message-ID: <28APR199400303608 at>
>Organization: Tufts University - Medford, MA
>News-Software: VAX/VMS VNEWS 1.41    
>I am mainly interested in the T7 repression this vector offers via the lac 
>operator, and I'm wondering if I need to cut out the pelB leader or just not
>worry about it.
>Any thoughts will be greatly appreciated.  Please respond by email or post in
>this group, which ever is most convenient.                      
>Pat Durham
>pdurham_pt4 at

It really depends upon what protein you are expressing. I assume you
are making a protein fusion in this vector. IF the protein you are
expressing is a secreted protein (i.e. is translated as a pre-protein
with a signal sequence) in its original state, then you probably
want to use the pel leader. IF you protein is NOT a secreted protein
then you may not want to use it. Many (but not all) proteins which are
not secreted proteins can NOT be secreted even when a signal peptide is
added to the amino terminus.

So it really depends upon what you are doing is the answer.

 Michael Benedik				INTERNET: Benedik at
 Dept. of Biochemical & Biophysical Sciences	
 University of Houston				BITNET: Benedik at uhou

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