SAR and X-ray. A new approach combining fragment-based screening and rational drug design: application to the discovery of nanomolar inhibitors of Src SH2.

(pp60)Src is a protein involved in signal transduction and is mainly expressed in neurones, platelets, and osteoclasts. Its precise biological role was recently discovered with the KO experiments by Soriano that gave rise to no other apparent phenotype than osteopetrosis, a disease resulting in excedent bone formation. The SH2 domain of the Src family specifically recognizes a sequence of tetrapeptide featuring a phosphotyrosine and a lipophilic aminoacid at the +1 and +3 positions.

Endogenous glutathione-binding proteins of insect cell lines: characterization and removal from glutathione S-transferase (GST) fusion proteins.

After affinity purification on immobilized glutathione, insect-cell-derived glutathione S-transferase (GST) fusion proteins contain variable amounts of protein contaminants of about 23-24 kDa. We have isolated these glutathione-binding proteins from the widely used Sf9 and Hi5 insect cell lines and characterized them by LC-MS and N-terminal sequencing. Based on the observation that these proteins have higher affinity for glutathione than GST fusions, we have found that by using differential elution conditions the amount of such contaminants in GST fusion preparations can be strongly reduced directly during the affinity purification step.