A synthetic polypeptide conjugate from a 42-residue polypeptide and salicylhydroxamic acid binds human myeloperoxidase with high affinity
Article first published online: 19 OCT 2012
Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
Journal of Peptide Science
Volume 18, Issue 12, pages 731–739, December 2012
How to Cite
Sun, X., Yang, J., Norberg, T. and Baltzer, L. (2012), A synthetic polypeptide conjugate from a 42-residue polypeptide and salicylhydroxamic acid binds human myeloperoxidase with high affinity. J. Peptide Sci., 18: 731–739. doi: 10.1002/psc.2459
- Issue published online: 13 NOV 2012
- Article first published online: 19 OCT 2012
- Manuscript Accepted: 21 SEP 2012
- Manuscript Revised: 12 SEP 2012
- Manuscript Received: 12 JUN 2012
- salicylhydroxamic acid;
Myeloperoxidase (MPO) is a 150 kD tetrameric heme protein consisting of two heavy chains and two light chains, which is present in neutrophils, white blood cells, at concentrations between 2% and 5% and plays an important role in the innate immune system. The MPO concentration in serum or plasma has been shown to be linked to the risk for cardiovascular diseases, and MPO is considered to be a high potential diagnostic biomarker. To develop a molecule that binds MPO, salicylhydroxamic acid (SHA), a substrate analog inhibitor of MPO with a KD = 2 μM, was conjugated to a designed set of 42-residue polypeptide scaffolds via 9- and 11-carbon atom aliphatic spacers to form 20 different protein binder candidates, and their interactions with MPO were evaluated by surface plasmon resonance analysis. The polypeptide conjugate 4C37L34C11SHA was found to bind to MPO with an affinity that could be estimated to have a dissociation constant of around 400 pM, nearly four orders of magnitude higher than that of SHA. Inhibition of binding to MPO by free SHA was observed in competition experiments demonstrating that the binding of the polypeptide conjugate is dominated by the interactions of SHA with the heme cavity. Although still in the future, the discovery of these new synthetic binders for MPO suggests a route to clinical diagnostic tests in vivo or in vitro, independent of antibodies. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.