Most drugs in common use are small organic molecules which interact functionally with proteins, either acting as ligands for receptors, inhibiting enzymes or blocking protein interactions, etc. Their activities have generally been established by specific cellular and molecular assays to determine mode of action. While frequently well tolerated, side-effects are nevertheless commonplace and can be the result of unexpected interference with unintended pathways in poorly understood ways. The consequences of off-target interactions may be clinically serious.
Such reactions can be investigated by a comprehensive screen against the >20,000 proteins on HuProt arrays, both to illuminate the mechanism of known side effects of established drugs or indicate target binding for drugs under development and which may warrant further investigation. Even where the array does not reflect the expected mechanism of the drug (e.g. against a GPCR for which folding may depend on membrane-bound expression) the discovery of unintended reactions is nevertheless an important clue to other actions so far unsuspected.
The process of screening small molecules on Huprot arrays essentially follows the assay layout for protein-protein or nucleic acid-protein interactions, but with the added issue of labelling small molecules in such a way as not to interfere with their reactivity or lead to misleading interactions caused by the modification. For peptides there is the possibility of labelling with biotin or fluorophore, but small molecules which as ligands become buried in a protein pocket or cleft, may be less amenable to chemical moiety labelling and alternative means of demonstrating the reaction may be required.
Please contact us to discuss the options and develop a strategy for your project.
See here for HuProt references in small molecule profiling.