Identification and specificity studies of small-molecule ligands for SH3 protein domains.
The Src Homology 3 (SH3) domains are small protein-protein interaction domains that bind proline-rich sequences and mediate a wide range of cell-signaling and other important biological processes. Since deregulated signaling pathways form the basis of many human diseases, the SH3 domains have been attractive targets for novel therapeutics. High-affinity ligands for SH3 domains have been designed; however, these have all been peptide-based and no examples of entirely nonpeptide SH3 ligands have previously been reported. Using the mouse Tec Kinase SH3 domain as a model system for structure-based ligand design, we have identified several simple heterocyclic compounds that selectively bind to the Tec SH3 domain. Using a combination of nuclear magnetic resonance chemical shift perturbation, structure-activity relationships, and site-directed mutagenesis, the binding of these compounds at the proline-rich peptide-binding site has been characterized. The most potent of these, 2-aminoquinoline, bound with Kd = 125 microM and was able to compete for binding with a proline-rich peptide. Synthesis of 6-substituted-2-aminoquinolines resulted in ligands with up to 6-fold improved affinity over 2-aminoquinoline and enhanced specificity for the Tec SH3 domain. Therefore, 2-aminoquinolines may potentially be useful for the development of high affinity small molecule ligands for SH3 domains.
School of Molecular and Biomedical Science, The University of Adelaide, SA, 5005, Australia.
Steven R
SR
Inglis
Cvetan
C
Stojkoski
Kim M
KM
Branson
Jacquie F
JF
Cawthray
Daniel
D
Fritz
Emma
E
Wiadrowski
Simon M
SM
Pyke
Grant W
GW
Booker
D000595:Amino Acid Sequence; D000634:Aminoquinolines / Q000138:chemical synthesis / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D005454:Fluorescence Polarization; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011392:Proline / Q000737:chemistry; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics; D011799:Quinazolines / Q000138:chemical synthesis / Q000737:chemistry; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D018909:src Homology Domains
D000634:Aminoquinolines; D008024:Ligands; D011799:Quinazolines; D011392:Proline; C089848:Tec protein-tyrosine kinase; D011505:Protein-Tyrosine Kinases