Cofactor binding protects flavodoxin against oxidative stress
| Autor: | Carlo P. M. van Mierlo, Robert H. H. van den Heuvel, Willem J. H. van Berkel, Simon Lindhoud, Willy A. M. van den Berg, Albert J. R. Heck |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Proteomics
Flavin Mononucleotide Flavodoxin Flavin mononucleotide lcsh:Medicine Protein Engineering Biochemistry chemistry.chemical_compound pseudomonas-fluorescens lcsh:Science 0303 health sciences Spectrometric Identification of Proteins Multidisciplinary cysteine sulfinic acid biology Chemistry 030302 biochemistry & molecular biology Chemical Reactions mass-spectrome sulfenic acid Oxidation-Reduction Research Article Protein Binding Protein Structure Stereochemistry Biophysics Biochemie Flavin group Protein Chemistry Cofactor beta parallel protein 03 medical and health sciences Biology VLAG 030304 developmental biology Azotobacter vinelandii Cofactor binding para-hydroxybenzoate hydroxylase hydrogen-peroxide Cofactors lcsh:R Proteins Hydrogen Peroxide alkyl hydroperoxide reductase Oxidative Stress methionine sulfoxide reductase biology.protein Cysteine sulfinic acid Sulfenic acid lcsh:Q Apoproteins azotobacter-vinelandii apoflavodoxin Oxidation-Reduction Reactions Cysteine |
| Zdroj: | PLoS ONE, Vol 7, Iss 7, p e41363 (2012) PLoS ONE 7 (2012) 7 PLoS ONE PLoS ONE, 7(7) |
| ISSN: | 1932-6203 |
| Popis: | In organisms, various protective mechanisms against oxidative damaging of proteins exist. Here, we show that cofactor binding is among these mechanisms, because flavin mononucleotide (FMN) protects Azotobacter vinelandii flavodoxin against hydrogen peroxide-induced oxidation. We identify an oxidation sensitive cysteine residue in a functionally important loop close to the cofactor, i.e., Cys69. Oxidative stress causes dimerization of apoflavodoxin (i.e., flavodoxin without cofactor), and leads to consecutive formation of sulfinate and sulfonate states of Cys69. Use of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) reveals that Cys69 modification to a sulfenic acid is a transient intermediate during oxidation. Dithiothreitol converts sulfenic acid and disulfide into thiols, whereas the sulfinate and sulfonate forms of Cys69 are irreversible with respect to this reagent. A variable fraction of Cys69 in freshly isolated flavodoxin is in the sulfenic acid state, but neither oxidation to sulfinic and sulfonic acid nor formation of intermolecular disulfides is observed under oxidising conditions. Furthermore, flavodoxin does not react appreciably with NBD-Cl. Besides its primary role as redox-active moiety, binding of flavin leads to considerably improved stability against protein unfolding and to strong protection against irreversible oxidation and other covalent thiol modifications. Thus, cofactors can protect proteins against oxidation and modification. |
| Databáze: | OpenAIRE |
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