two plasmids of the same protein with tags on N and C-terminus. - how can I make use of them? (Sep/07/2006 )
just a question that crossed my mind 
i have two vectors of the same protein (insert). in one tag is attached to the N-terminus and another one tag attached to the C-terminus. my protein is extremely unstable. can I make use of this for example make double tag or for some functional studies?? to study proteolysis? 
i appreciate your ideas very much.
i have two vectors of the same protein (insert). in one tag is attached to the N-terminus and another one tag attached to the C-terminus. my protein is extremely unstable. can I make use of this for example make double tag or for some functional studies?? to study proteolysis? i appreciate your ideas very much.I was not clear what purpose is your research? Would an artificial tag be very meaningful to you?
One thing to avoid is not to introduce two variables at one time. Try either C-terminal fusion, or N-termial fusion first, then move on.
It is (probably) the size, sequence and the 3-D compact struture of the tags mattter more in protein degradation rate.
I am wondering if the tags r making ur protien unstable.
Anyways, the influence of a tag on the protien is not easily predictable so to do some functional studies with tags on both ends is not advisable.
Isnt it possible to try ur experiments with a single tag and then comapre it to the double tagged one.
But an important question is, is this really going to help u to understand the function of the protien?
well if you need to purify your protein, the position of the tag may be critical for that (accessibility at most).
Then if purification are roughly equal, the presence of a tag may disturb conformationnal strucutre of your prot thus altering its activity.
I would try both of them.