title: Post-translational tyrosine nitration of eosinophil granule toxins mediated by eosinophil peroxidase.
abstract: Nitration of tyrosine residues has been observed during various acute and chronic inflammatory diseases. However, the mechanism of tyrosine nitration and the nature of the proteins that become tyrosine nitrated during inflammation remain unclear. Here we show that eosinophils but not other cell types including neutrophils contain nitrotyrosine-positive proteins in specific granules. Furthermore, we demonstrate that the human eosinophil toxins, eosinophil peroxidase (EPO), major basic protein, eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP), and the respective murine toxins, are post-translationally modified by nitration at tyrosine residues during cell maturation. High resolution affinity-mass spectrometry identified specific single nitration sites at Tyr349 in EPO and Tyr33 in both ECP and EDN. ECP and EDN crystal structures revealed and EPO structure modeling suggested that the nitrated tyrosine residues in the toxins are surface exposed. Studies in EPO(-/-), gp91phox(-/-), and NOS(-/-) mice revealed that tyrosine nitration of these toxins is mediated by EPO in the presence of hydrogen peroxide and minute amounts of NOx. Tyrosine nitration of eosinophil granule toxins occurs during maturation of eosinophils, independent of inflammation. These results provide evidence that post-translational tyrosine nitration is unique to eosinophils.
authors.affiliation: Institute of Medical Microbiology and Hygiene, Universitätsklinikum Tübingen, Tübingen 72074, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Ulrich
authors.forename: Alina
authors.initials: A
authors.lastname: Petre
authors.forename: Nikolay
authors.initials: N
authors.lastname: Youhnovski
authors.forename: Franziska
authors.initials: F
authors.lastname: Prömm
authors.forename: Markus
authors.initials: M
authors.lastname: Schirle
authors.forename: Michael
authors.initials: M
authors.lastname: Schumm
authors.forename: Ralph S
authors.initials: RS
authors.lastname: Pero
authors.forename: Alfred
authors.initials: A
authors.lastname: Doyle
authors.forename: James
authors.initials: J
authors.lastname: Checkel
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kita
authors.forename: Nethaji
authors.initials: N
authors.lastname: Thiyagarajan
authors.forename: K Ravi
authors.initials: KR
authors.lastname: Acharya
authors.forename: Peter
authors.initials: P
authors.lastname: Schmid-Grendelmeier
authors.forename: Hans-Uwe
authors.initials: HU
authors.lastname: Simon
authors.forename: Heinz
authors.initials: H
authors.lastname: Schwarz
authors.forename: Masato
authors.initials: M
authors.lastname: Tsutsui
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimokawa
authors.forename: Gabriel
authors.initials: G
authors.lastname: Bellon
authors.forename: James J
authors.initials: JJ
authors.lastname: Lee
authors.forename: Michael
authors.initials: M
authors.lastname: Przybylski
authors.forename: Gerd
authors.initials: G
authors.lastname: Döring
mesh_terms: D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray / Q000379:methods; D047209:Eosinophil Peroxidase / Q000737:chemistry*; D004804:Eosinophils / Q000378:metabolism*; D006801:Humans; D007249:Inflammation; D008168:Lung / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009498:Neurotoxins / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D014443:Tyrosine / Q000737:chemistry
chemical_list: D009498:Neurotoxins; D014443:Tyrosine; D047209:Eosinophil Peroxidase; D009584:Nitrogen