Small nonphosphorylated Grb2-SH2 domain antagonists evaluated by surface plasmon resonance technology
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Feng-Di T Lung1, Chiung-Wen Chang, Meng-Chin Chong
1Department of Chemistry, Tunghai University, Taichung, Taiwan, Republic of China. fdlung@mail.thu.edu.tw
Abstract:
The growth factor receptor-binding protein-Src homology 2 (Grb2-SH2) domain plays an important role in the oncogenic Ras signal transduction pathway, which involves cell proliferation and differentiation. Therefore, the Grb2-SH2 domain has been chosen as our target for development of potential antiproliferative agents. Herein, we report the study of the inhibitory effects of small nonphosphorylated peptide analogs interacting with the Grb2-SH2 domain protein by surface plasmon resonance (SPR) technology. A set of 8 related peptide analogs were synthesized, purified, and characterized. Their inhibitory effects on Grb2-SH2 were evaluated by the SPR technology developed with the BIACORE X instrument. The lead peptide, Fmoc-Glu-Tyr-Aib-Asn-NH2 (Fmoc-E-Y-Aib-N; Fmoc: 9-fluorenylmethyoxycarbonyl; Aib=alpha-amino isobutyric acid) inhibited Grb2-SH2 domain function with an IC50 value of 8.7 microM. A molecular modeling study of the lead peptide indicated that the glutamate in the Fmoc peptide is ideally positioned to form a strong salt bridge to Arg 67 in the Grb2-SH2 domain, using both its backbone carbonyl and its acidic group. Residue Glu 89 in Grb2-SH2 flips inward to fill the binding site and partially replace the phosphate group as a hydrogen-bond acceptor. Results of these studies provide important information for further development of potent nonphosphorylated peptide inhibitors of the Grb2-SH2 domain.
Insights
Researchers developed small peptide analogs to inhibit the Grb2-SH2 domain, crucial in cancer pathways. The lead peptide, Fmoc-E-Y-Aib-N, showed significant antiproliferative effects, offering potential for new cancer therapies.
Area of Science:
- Biochemistry
- Molecular Biology
- Medicinal Chemistry
Background:
- The Grb2-SH2 domain is integral to the Ras signal transduction pathway, regulating cell proliferation and differentiation.
- Dysregulation of this pathway is implicated in oncogenesis, making the Grb2-SH2 domain a target for antiproliferative drug development.
Purpose of the Study:
- To investigate the inhibitory effects of small, nonphosphorylated peptide analogs on the Grb2-SH2 domain.
- To identify potent peptide inhibitors for potential antiproliferative agents.
Main Methods:
- Synthesis, purification, and characterization of eight related peptide analogs.
- Evaluation of inhibitory effects using surface plasmon resonance (SPR) technology on a BIACORE X instrument.
- Molecular modeling to elucidate the binding interactions of the lead peptide with the Grb2-SH2 domain.
Main Results:
- The lead peptide, Fmoc-Glu-Tyr-Aib-Asn-NH2 (Fmoc-E-Y-Aib-N), demonstrated significant inhibition of Grb2-SH2 domain function with an IC50 of 8.7 microM.
- Molecular modeling revealed key interactions, including a salt bridge between the peptide's glutamate and Arg 67, and inward flipping of Grb2-SH2 residue Glu 89.
- These interactions suggest a mechanism where the peptide mimics or replaces the function of the phosphate group in binding.
Conclusions:
- The developed nonphosphorylated peptide analogs show promise as inhibitors of the Grb2-SH2 domain.
- The lead peptide, Fmoc-E-Y-Aib-N, provides a foundation for designing more potent antiproliferative agents targeting the Ras pathway.
- These findings offer valuable insights for the rational design of novel peptide-based therapeutics for cancer treatment.
