Domain poisoning in chemogenomics queries. (a) The schematic shows the domain structure of a protein in a hypothetical query - the rat Tyrosine-protein phosphatase Syp (P35235) - and one of the hits, retrieved from a BLAST query against the ChEMBL target dictionary - the rat Tyrosine-protein kinase SYK (Q64725). The relatively low expectation value for this query comes from high scoring alignments of the SH2 domains. At the same time, the overlap between small molecules binding both proteins is expected to be low.
Kruger et al. BMC Bioinformatics 2012 13(Suppl 17):S11 doi:10.1186/1471-2105-13-S17-S11