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.
Inglis
Steven R
SR
School of Molecular and Biomedical Science, The University of Adelaide, SA, 5005, Australia.
Stojkoski
Cvetan
C
Branson
Kim M
KM
Cawthray
Jacquie F
JF
Fritz
Daniel
D
Wiadrowski
Emma
E
Pyke
Simon M
SM
Booker
Grant W
GW
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