Oxidative Post-translational Modifications Accelerate Proteolytic Degradation of Calprotectin
Name
nihms-1028296.pdf
Description
Accepted version
Size
1.21 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Stephan, Jules R.
Yu, Fangting
Costello, Rebekah M.
Bleier, Benjamin S.
Nolan, Elizabeth Marie
Date Issued
October 2018
Journal
Journal of the American Chemical Society
Publisher
American Chemical Society (ACS)
Citation
Stephan, Jules R. et al. "Oxidative Post-translational Modifications Accelerate Proteolytic Degradation of Calprotectin" Journal of the American Chemical Society 140, 50 (October 2018): 17444-17455 © 2018 American Chemical Society
Version
Author's final manuscript
Abstract
Oxidative post-translational modifications affect the structure and function of many biomolecules. Herein we examine the biophysical and functional consequences of oxidative post-translational modifications to human calprotectin (CP, S100A8/S100A9 oligomer, MRP8/MRP14 oligomer, calgranulins A/B oligomer). This abundant metal-sequestering protein contributes to innate immunity by starving invading microbial pathogens of transition metal nutrients in the extracellular space. It also participates in the inflammatory response. Despite many decades of study, little is known about the fate of CP at sites of infection and inflammation. We present compelling evidence for methionine oxidation of CP in vivo, supported by using [superscript 15]N-labeled CP-Ser (S100A8(C42S)/S100A9(C3S)) to monitor for adventitious oxidation following human sample collection. To elucidate the biochemical and functional consequences of oxidative post-translational modifications, we examine recombinant CP-Ser with methionine sulfoxide modifications generated by exposing the protein to hydrogen peroxide. These oxidized species coordinate transition metal ions and exert antibacterial activity. Nevertheless, oxidation of M81 in the S100A9 subunit disrupts Ca(II)-induced tetramerization and, in the absence of a transition metal ion bound at the His[subscript 6] site, accelerates proteolytic degradation of CP. We demonstrate that native CP, which contains one Cys residue in each full-length subunit, forms disulfide bonds within and between S100A8/S100A9 heterodimers when exposed to hydrogen peroxide. Remarkably, disulfide bond formation accelerates proteolytic degradation of CP. We propose a new extension to the working model for extracellular CP where post-translational oxidation by reactive oxygen species generated during the neutrophil oxidative burst modulates its lifetime in the extracellular space. Keywords: disulfides; peptides and proteins; monomersIons; oxidation
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.1021/jacs.8b06354
