| Autor: |
Samygina VR; Institute of Crystallography RAS, Moscow, Russia. vsamygina@cicbiogune.es, Sokolov AV, Bourenkov G, Petoukhov MV, Pulina MO, Zakharova ET, Vasilyev VB, Bartunik H, Svergun DI |
| Jazyk: |
angličtina |
| Zdroj: |
PloS one [PLoS One] 2013 Jul 03; Vol. 8 (7), pp. e67145. Date of Electronic Publication: 2013 Jul 03 (Print Publication: 2013). |
| DOI: |
10.1371/journal.pone.0067145 |
| Abstrakt: |
Copper-containing ferroxidase ceruloplasmin (Cp) forms binary and ternary complexes with cationic proteins lactoferrin (Lf) and myeloperoxidase (Mpo) during inflammation. We present an X-ray crystal structure of a 2Cp-Mpo complex at 4.7 Å resolution. This structure allows one to identify major protein-protein interaction areas and provides an explanation for a competitive inhibition of Mpo by Cp and for the activation of p-phenylenediamine oxidation by Mpo. Small angle X-ray scattering was employed to construct low-resolution models of the Cp-Lf complex and, for the first time, of the ternary 2Cp-2Lf-Mpo complex in solution. The SAXS-based model of Cp-Lf supports the predicted 1:1 stoichiometry of the complex and demonstrates that both lobes of Lf contact domains 1 and 6 of Cp. The 2Cp-2Lf-Mpo SAXS model reveals the absence of interaction between Mpo and Lf in the ternary complex, so Cp can serve as a mediator of protein interactions in complex architecture. Mpo protects antioxidant properties of Cp by isolating its sensitive loop from proteases. The latter is important for incorporation of Fe(3+) into Lf, which activates ferroxidase activity of Cp and precludes oxidation of Cp substrates. Our models provide the structural basis for possible regulatory role of these complexes in preventing iron-induced oxidative damage. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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