I've prepared a rabbit polyclonal antiserum against a protein of
interest. From immunoblots, it appears that the antiserum is
crossreacting with the large subunit of Rubisco to make a big fat
band. Since the antigen was protein that was produced in bacteria, I
think any cross reactivity must just be coincidental. Also, the pre-
immune serum, did not have any problem with rubisco crossreactivity.
I haven't found any obvious stretches of sequence similarity between
rubisco and my protein of interest to account for the
crossreactivity, but I think it can be hard to make predictions about
antibody cross-reactivity based on sequence alone. Unfortunately, the
protein I would like to detect with the antiserum is very similar in
size to Rubisco. I'm worried I won't be able to detect "real" signal
from my protein of interest because of the big fat Rubisco band.
Has anybody had a similar problem, and if so, are there any
solutions? Might different blocking agents help (I'm currently using
5% NFDM in TBS)? Can one do a more "stringent" wash to eliminate
unwanted signals. Currently, I'm thinking the best strategy might be
to express Rubisco in bacteria and use the lysate to preadsorb the
antiserum. Has anybody here tried that strategy before?
Thanks for any input.
Michael L. Sullivan
Plant Research Molecular Geneticist
US Dairy Forage Research Center
1925 Linden Drive West
Madison, WI 53706
(608) 890-0046 (Phone)
(608) 890-0076 (FAX)