Pinpointing the interaction site between semaphorin-3A and its inhibitory peptide |
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Authors: | Kevin Kretschmer Jan Stichel Kathrin Bellmann-Sickert Lars Baumann Donald Bierer Bernd Riedl Annette G. Beck-Sickinger |
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Affiliation: | 1. Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Leipzig, Germany;2. Bayer AG, Wuppertal, Germany |
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Abstract: | Semaphorin-3A (Sema-3A) is a chemorepellant protein with various biological functions, including kidney development. It interacts with a protein complex consisting of the receptors neuropilin-1 (NRP-1) and plexin-A1. After acute kidney injury, Sema-3A is overexpressed and secreted, leading to a loss of kidney function. The development of peptide inhibitors is a promising approach to modulate the interaction of Sema-3A with its receptor NRP-1. Few interaction points between these binding partners are known. However, an immunoglobulin-like domain-derived peptide of Sema-3A has shown a positive effect on cell proliferation. To specify these interactions between the peptide inhibitor and the Sema-3A–NRP-1 system, the peptides were modified with the photoactivatable amino acids 4-benzoyl-l -phenylalanine or photo-l -leucine by solid-phase peptide synthesis. Activity was tested by an enzyme-linked immunosorbent-based binding assay, and crosslinking experiments were analyzed by Western blot and mass spectrometry, demonstrating a specific binding site of the peptide at Sema-3A. The observed signals for Sema-3A-peptide interaction were found in a defined area of the Sema domain, which was also demonstrated to be involved in NRP-1 binding. The presented data identified the interaction site for further development of therapeutic peptides to treat acute kidney injury by blocking the Sema-3A–NRP-1 interaction. |
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Keywords: | ELISA inhibition photo-crosslinking protein–protein interaction Sema-3A therapeutic peptides |
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