Description of New Interaction Motives with the Surface Receptors VEGFR-1, NRP-1, IL-1RI e IL-11Ra using Nuclear Magnetic Resonance and Phage Display
Anobom, C. D1; Giordano, R. J2; Cardó-vila, M2; Zurita, A. J; Kalil, J3; Pasqualini, R2; Arap, W2; Valente, A. P1 and Almeida, F. C. L1.
1Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, IBqM, UFRJ, RJ;
2M. D. Anderson Cancer Center, Houston, Texas;
3Instituto do Coração, USP, São Paulo.
Phage display (Pd) and NMR have been used to select biological active peptides. NMR monitors low-affinity peptide-receptor binding. NMR signal shows up as an average between the free and bound state, if the binding equilibrium is in fast exchange regime. We have used chemical shift changes and longitudinal relaxation time as probes for peptide-receptor interactions. The goal of this work was to map by NMR peptides selected from Pd libraries in 3 different biological systems. The I is related with VEGF and their receptors; II and III are related with the interleukins.
CPQPRPLC peptide selected from Pd interacts with VEGFR-1 and NRP-1 receptors. This peptide displays multiple conformations when free in solution. The new motif RPL interacts with both receptors. Pro binds to NRP-1 and not to VEGFR-1, explaining the higher affinity to NRP-1. Interaction studies with the recombinant domains 2 and 3 of VEGFR-1 have been carried out, suggesting that RPL binds to D3.
Masa45 peptide was selected from Pd using lymphocytes T of cardiac tissues isolated from patients with rheumatic fever. Masa45 is homologous to the IL-1Ra that binds to the IL-1RI receptor. Masa45 does not interact with IL1RII but does with IL1RI. Interaction is mediated by a motif C1/12, M4, E5, A6 and Y11. Our data indicate the participation of the new motif MEA in the interaction that could be a model to the understanding and study of new targets related to autoimmune diseases.
IL11pep was targeted to prostate endothelial cells after in vivo injection of Pd library. IL11pep was selected due to its homology with IL11. Interaction studies indicate that the peptide binds to the IL11Ra receptor. Literature data indicate that IL11 binds to the receptor by domain I. Our data show a new interaction motif, formed by the BC loop. The new motif is RRAGGS. These results supply new information to the development of active compounds against prostate cancer and also that function as a targeting molecule to prostate tissue.
Acknowlegments: CNPq, FAPERJ, Pronex, FINEP, ICGEB
|