4X6S

Grb7 SH2 domain with phosphotyrosine mimetic inhibitor peptide

Summary for 4X6S

• Entry DOI: 10.2210/pdb4x6s/pdb
• Descriptor: Growth factor receptor-bound protein 7, Phosphotyrosine mimetic inhibitor peptide G7-TEM1 (3 entities in total)
• Functional Keywords: src homology domain, inhibitor, phosphotyrosine binding pocket, signaling protein-inhibitor complex, signaling protein/inhibitor
• Biological source: Homo sapiens (Human); More
• Cellular location: Cytoplasm: Q14451
• Total number of polymer chains: 4
• Total formula weight: 28080.05

Authors

Watson, G.M.,Panjikar, S.,Wilce, M.C.,Wilce, J.A. (deposition date: 2014-12-09, release date: 2015-09-23, Last modification date: 2015-10-28)

Primary citation

Watson, G.M.,Gunzburg, M.J.,Ambaye, N.D.,Lucas, W.A.,Traore, D.A.,Kulkarni, K.,Cergol, K.M.,Payne, R.J.,Panjikar, S.,Pero, S.C.,Perlmutter, P.,Wilce, M.C.,Wilce, J.A.
Cyclic Peptides Incorporating Phosphotyrosine Mimetics as Potent and Specific Inhibitors of the Grb7 Breast Cancer Target.
J.Med.Chem., 58:7707-7718, 2015

PubMed Abstract: The Grb7 adaptor protein is a therapeutic target for both TNBC and HER2+ breast cancer. A nonphosphorylated cyclic peptide 1 (known as G7-18NATE) inhibits Grb7 via targeting the Grb7-SH2 domain, but requires the presence of phosphate ions for both affinity and specificity. Here we report the discovery of malonate bound in the phosphotyrosine binding pocket of the apo-Grb7-SH2 structure. Based on this, we carried out the rational design and synthesis of two analogues of peptide 1 that incorporate carboxymethylphenylalanine (cmF) and carboxyphenylalanine (cF) as mimics of phosphotyrosine (pY). Binding studies using SPR confirmed that affinity for Grb7-SH2 domain is improved up to 9-fold over peptide 1 under physiological phosphate conditions (KD = 2.1-5.7 μM) and that binding is specific for Grb7-SH2 over closely related domains (low or no detectable binding to Grb2-SH2 and Grb10-SH2). X-ray crystallographic structural analysis of the analogue bearing a cmF moiety in complex with Grb7-SH2 has identified the precise contacts conferred by the pY mimic that underpin this improved molecular interaction. Together this study identifies and characterizes the tightest specific inhibitor of Grb7 to date, representing a significant development toward a new Grb7-targeted therapeutic.

PubMed: 26359549
DOI: 10.1021/acs.jmedchem.5b00609

Experimental method

X-RAY DIFFRACTION (2.55 Å)