title: Ligands for the tyrosine kinase p56lck SH2 domain: discovery of potent dipeptide derivatives with monocharged, nonhydrolyzable phosphate replacements.
abstract: p56lck is a member of the src family of tyrosine kinases. Through modular binding units called SH2 domains, p56lck promotes phosphotyrosine-dependent protein-protein interactions and plays a critical role in signal transduction events that lead to T-cell activation. Starting from the phosphorylated dipeptide (2), a high-affinity ligand for the p56lck SH2 domain, we have designed novel dipeptides that contain monocharged, nonhydrolyzable phosphate group replacements and bind to the protein with KD's in the low micromolar range. Replacement of the phosphate group in phosphotyrosine-containing sequences by a (R/S)-hydroxyacetic (compound 8) or an oxamic acid (compound 10) moiety leads to hydrolytically stable, monocharged ligands, with 83- and 233-fold decreases in potency, respectively. This loss in binding affinity can be partially compensated for by incorporating large lipophilic groups at the inhibitor N-terminus. These groups provide up to 13-fold increases in potency depending on the nature of the phosphate replacement. The discovery of potent (2-3 microM), hydrolytically stable dipeptide derivatives, bearing only two charges at physiological pH, represents a significant step toward the discovery of compounds with cellular activity and the development of novel therapeutics for conditions associated with undesired T-cell proliferation.
authors.affiliation: Boehringer Ingelheim Pharmaceuticals Inc., 175 Briar Ridge Road, Ridgefield, Connecticut 06877, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Beaulieu
authors.forename: D R
authors.initials: DR
authors.lastname: Cameron
authors.forename: J M
authors.initials: JM
authors.lastname: Ferland
authors.forename: J
authors.initials: J
authors.lastname: Gauthier
authors.forename: E
authors.initials: E
authors.lastname: Ghiro
authors.forename: J
authors.initials: J
authors.lastname: Gillard
authors.forename: V
authors.initials: V
authors.lastname: Gorys
authors.forename: M
authors.initials: M
authors.lastname: Poirier
authors.forename: J
authors.initials: J
authors.lastname: Rancourt
authors.forename: D
authors.initials: D
authors.lastname: Wernic
authors.forename: M
authors.initials: M
authors.lastname: Llinas-Brunet
authors.forename: R
authors.initials: R
authors.lastname: Betageri
authors.forename: M
authors.initials: M
authors.lastname: Cardozo
authors.forename: E R
authors.initials: ER
authors.lastname: Hickey
authors.forename: R
authors.initials: R
authors.lastname: Ingraham
authors.forename: S
authors.initials: S
authors.lastname: Jakes
authors.forename: A
authors.initials: A
authors.lastname: Kabcenell
authors.forename: T
authors.initials: T
authors.lastname: Kirrane
authors.forename: S
authors.initials: S
authors.lastname: Lukas
authors.forename: U
authors.initials: U
authors.lastname: Patel
authors.forename: J
authors.initials: J
authors.lastname: Proudfoot
authors.forename: R
authors.initials: R
authors.lastname: Sharma
authors.forename: L
authors.initials: L
authors.lastname: Tong
authors.forename: N
authors.initials: N
authors.lastname: Moss
mesh_terms: D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D013329:Structure-Activity Relationship; D018909:src Homology Domains
chemical_list: D004151:Dipeptides; D008024:Ligands; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)