title: Multiplexed detection of protein-peptide interaction and inhibition using capillary electrophoresis.
abstract: High-speed capillary electrophoresis (CE) was employed to detect binding and inhibition of SH2 domain proteins using fluorescently labeled phosphopeptides as affinity probes. Single SH2 protein-phosphopeptide complexes were detected and confirmed by competition and fluorescence anisotropy. The assay was then extended to a multiplexed system involving separation of three SH2 domain proteins: Src, SH2-Bbeta, and Fyn. The selectivity of the separation was improved by altering the charge of the peptide binding partners used, thus demonstrating a convenient way to control resolution for the multiplexed assay. The separation was completed within 6 s, allowing rapidly dissociating complexes to be detected. Two low molecular weight inhibitors were tested for inhibition selectivity and efficacy. One inhibitor interrupted binding interaction of all three proteins, while the other selectively inhibited Src only leaving SH2-Bbeta and Fyn complex barely affected. IC(50) of both selective and nonselective inhibitors were determined and compared for different proteins. The IC(50) of the nonselective inhibitor was 49 +/- 9, 323 +/- 42, and 228 +/- 19 microM (n = 3) for Src, SH2-Bbeta, and Fyn, respectively, indicating different efficacy of the nonselective inhibitor for different SH2 domain protein. It is concluded that high-speed CE has the potential for multiplexed screening of drugs that disrupt protein-protein interactions.
authors.affiliation: Department of Chemistry, University of Michigan, 930 North University, Ann Arbor, Michigan 48109-1055, USA.
authors.forename: Peilin
authors.initials: P
authors.lastname: Yang
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Whelan
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Mao
authors.forename: Angel W-M
authors.initials: AW
authors.lastname: Lee
authors.forename: Christin
authors.initials: C
authors.lastname: Carter-Su
authors.forename: Robert T
authors.initials: RT
authors.lastname: Kennedy
mesh_terms: D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D010455:Peptides / Q000032:analysis* / Q000037:antagonists & inhibitors; D011485:Protein Binding; D011506:Proteins / Q000032:analysis* / Q000037:antagonists & inhibitors; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; D010455:Peptides; D011506:Proteins