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
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