Patent ID: 6432651
Filing Date: 2002-08-13
Classification: G01N

Abstract:
A method of screening complex biological material for and characterizing any candidate ligand that binds to a selected target at or above a selected binding strength, the method comprising the steps of:(1) providing a complex biological sample; (2) combining the complex biological sample with a predetermined concentration of the selected target to form a sample/target mixture; (3) injecting a plug of the sample/target mixture from step (2) into an inlet end of a conduit of a capillary electrophoresis instrument; (4) subjecting compounds within the sample/target plug to capillary electrophoresis under first predetermined conditions, wherein the first predetermined conditions are optimized so that a detectable amount of any complex(es) formed between the target and any candidate ligand(s) binding to the target at or above a first selected binding strength, remains bound for a substantial portion of the capillary electrophoresis run time, and so that a substantial amount of any additional complex(es) formed between the target and any additional ligand(s) binding to the target below the selected binding strength, dissociates before reaching the outlet end of the conduit; (5) introducing the electrophoresed sample/target compounds exiting from the capillary electrophoresis instrument into an on-line mass spectrometer interfaced with the capillary electrophoresis instrument; (6) subjecting the electrophoresed sample/target plug compounds to ionization and mass spectrometry analysis; (7) examining a capillary electrophoretic profile of the sample/target plug, the capillary electrophoretic profile having been generated either by tracking the target's migration during capillary electrophoresis in step (4) or by mass spectrometry analysis in step (6), and determining whether the sample/target plug's profile indicates the presence of a candidate ligand in the complex biological sample; (8) using mass spectrometry data from step (6) to determine a mass of any candidate target-binding ligand detected; and (9) repeating steps (3)-(8) at least once, wherein each repeat of step (4) is performed under other predetermined conditions that differ from the first predetermined conditions and from predetermined conditions in any other repeat of step (4), and wherein the other predetermined conditions are optimized for detecting candidate ligands binding to the target at a selected binding strength different from the first selected binding strength and from a selected binding strength in any other repeat of step (4).