Hello All, I was wondering whether anybody has a reference in which the following method is used:
Integral Membrane Protein (IMP) Topology by MS Fingerprinting. Express IMP, subject whole cells to membrane-impermeable, membrane-soluble, and membrane-crossing, lysine-specific reagents to label all free lysines in each compartment (i.e., extracellular, membrane-spanning, and intracellular (and buried, which would not get labeled)). Then do rudimentary purification, run a gel, cut out the band, run trypsinolysis-based fingerprinting, and compare the weights of the fragments with the unlabelled. Those bands with a shift would have been exposed to the reagent in that experiment, indicating that fragment/lysine's location with respect to the cell membrane. I suspect that somebody must have thought of this previously...there is nothing new under the sun. Jacob Keller
