I'm hoping someone might have some ideas on how to prepare a sample for
maldi in the following situation:
I am working with intact phage and get strong signal for the coat protein
(46 AA's, 5kDa) in aCN and a variety of other matrices. After performing a
chemical cleavage at AA37, a 1000 dalton C-terminal fragment is generated
and both the 5 kda parent and the 1 kda are visible in the spectra.
Allowing the cleavage to continue to excess results in almost complete
depletion of the parent in the maldi spectra which are dominated by a strong
peak from the 1kda fragment.
The problem is that I have never seen the other fragement (4 kda) that would
be generated in the cleavage. The abundant presence of the small fragment
indicates that the large part must also be there, but it never seems to fly.
The small fragement (9 residues) contains both K and R.
The large fragment contains mostly G,A,V,L,I with a few D,F,N,Q,P,S,T.
There are no K, R or H.
If any one has any tips on how I might get signal out of this larger
fragment, they would be greatly appreciated.
Cheers,
Matthew
Mr. Matthew P. Sampson
Department of Biochemistry
University of Cambridge
Tennis Court Road
Old Addenbrookes Site
Cambridge CB2 1GA UK
Tel: 01223-333638/766039
Fax: 01223-766002
International: +44-1223-333638/766039 (fax:-766002)
http://www.bio.cam.ac.uk/proj/adr/PNAC/pnac.html
http://www.bio.cam.ac.uk/dept/biochem