title: Automated affinity chromatography measurements of compound mixtures using a lab-on-valve apparatus coupled to electrospray ionization mass spectrometry.
abstract: We report a fully automated affinity chromatography system using a lab-on-valve (LOV) apparatus coupled to an electrospray ionization ion-trap mass spectrometer (ESI-MS). The system allows simultaneous measurements of multiple ligand affinities to proteins immobilized on beads. Bead regeneration, column repacking, and repetitive measurements are achieved on the time scale of several minutes. In this study, the system was used to screen the binding of a peptide mixture to human and Trypanosoma brucei (T. brucei) truncated Pex5 (tPex5) proteins. Equilibrium dissociation constants (K(d)) were measured for T. brucei tPex5 and compared to the values obtained by a fluorescence-based competition assay. The three peptides that showed affinity toward tPex5 had K(d) values that were comparable in magnitude (within a factor of 5) and showed the same ranking order as those from manual fluorescence measurements. With 12 min of sample infusion, the entire sample-to-sample cycle takes about 15 min and can be repeated without any preparation between runs. For T. brucei tPex5 affinity measurements, 1 mg of protein was sufficient for 35 repetitive analyses in the automated LOV-ESI-MS apparatus. The system allows rapid determination of K(d) in the range of 10(-5)-10(-7) M for sample mixtures and is suitable for screening a large number of compounds against multiple proteins.
authors.affiliation: Department of Chemistry, University of Washington, Seattle, WA 98195, USA.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ogata
authors.forename: Louis
authors.initials: L
authors.lastname: Scampavia
authors.forename: Tyan L
authors.initials: TL
authors.lastname: Carter
authors.forename: Erkang
authors.initials: E
authors.lastname: Fan
authors.forename: Frantisek
authors.initials: F
authors.lastname: Turecek
mesh_terms: D000818:Animals; D001331:Automation / Q000295:instrumentation*; D002846:Chromatography, Affinity; D006801:Humans; D010455:Peptides / Q000737:chemistry*; D000074435:Peroxisome-Targeting Signal 1 Receptor; D015800:Protozoan Proteins / Q000737:chemistry*; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D014346:Trypanosoma brucei brucei / Q000737:chemistry*
chemical_list: C000614264:PEX5 protein, human; D010455:Peptides; D000074435:Peroxisome-Targeting Signal 1 Receptor; D015800:Protozoan Proteins; D018160:Receptors, Cytoplasmic and Nuclear