Abstract
Chemokines are a group of chemotaxis proteins that regulate cell trafficking and play important roles in immune responses and inflammation. Ticks are blood-sucking parasites that secrete numerous immune-modulatory agents in their saliva to evade host immune responses. Evasin-3 is a small salivary protein that belongs to a class of chemokine-binding proteins isolated from the brown dog tick, Rhipicephalus sanguineus. Evasin-3 has been shown to have a high affinity for chemokines CXCL1 and CXCL8 and to diminish inflammation in mice. In the present study, solution NMR spectroscopy was used to investigate the structure of Evasin-3 and its CXCL8-Evasin-3 complex. Evasin-3 is found to disrupt the glycosaminoglycan-binding site of CXCL8 and inhibit the interaction of CXCL8 with CXCR2. Structural data were used to design two novel CXCL8-binding peptides. The linear tEv3 17-56 and cyclic tcEv3 16-56 dPG Evasin-3 variants were chemically synthesized by solid-phase peptide synthesis. The affinity of these newly synthesized variants to CXCL8 was measured by surface plasmon resonance biosensor analysis. The K-d values of tEv3 17-56 and tcEv3 16-56 dPG were 27 and 13 nm, respectively. Both compounds effectively inhibited CXCL8-induced migration of polymorphonuclear neutrophils. The present results suggest utility of synthetic Evasin-3 variants as scaffolds for designing and fine-tuning new chemokine-binding agents that suppress immune responses and inflammation.
Original language | English |
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Pages (from-to) | 12370-12379 |
Number of pages | 10 |
Journal | Journal of Biological Chemistry |
Volume | 294 |
Issue number | 33 |
DOIs | |
Publication status | Published - 16 Aug 2019 |
Keywords
- chemokine
- peptide chemical synthesis
- nuclear magnetic resonance (NMR)
- protein structure
- protein-protein interaction
- C-X-C motif chemokine ligand (CXCL)
- CHEMOKINE-BINDING-PROTEINS
- CYSTINE KNOT
- WEB SERVER
- MONOCLONAL-ANTIBODY
- RECEPTOR CXCR1
- XPLOR-NIH
- INTERLEUKIN-8
- RECOGNITION
- SELECTIVITY
- STABILITY