Study of FK-binding protein: FK506-metabolite complexes by electrospray mass spectrometry: correlation to immunosuppressive activity.
Electrospray ionization mass spectrometry was used to study several non-covalent FK-binding protein (FKBP) immunosuppressant complexes in the gas phase. Relative FKBP binding affinities were determined from the signal ratio for the 7+ charge states of bound and unbound complexes as a function of capillary exit voltage. All complexes displayed a 1:1 binding stoichiometry. The relative gas-phase binding affinities were found to be well correlated with in vitro FKBP binding and in vitro immunosuppression (rapamycin > FK506 > or = 31-demethyl FK506 > 13-demethyl FK506 >> Cyclosporin A; CsA). The method demonstrates potential as a simple, rapid, and automatable technique for prediction of the immunosuppressive activity of FKBP:drug complexes.
Trepanier
D J
DJ
Isotechnika Inc., Edmonton, Alberta, Canada.
Abel
M D
MD
Freitag
D G
DG
Yatscoff
R W
RW
D006801:Humans; D020104:Immunophilins / Q000032:analysis*; D007166:Immunosuppressive Agents / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*; D011994:Recombinant Proteins / Q000032:analysis; D013329:Structure-Activity Relationship; D022021:Tacrolimus Binding Proteins
D007166:Immunosuppressive Agents; D011994:Recombinant Proteins; D022021:Tacrolimus Binding Proteins; D020104:Immunophilins