Detection of reversible protein thiol modifications in tissues

Rogers, Lynette K.; Leinweber, Barbara L.; Smith, Charles V.

doi:10.1016/j.ab.2006.08.020

Cited by 77 publications

(94 citation statements)

References 34 publications

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“…Although the effect of electrospray ionization in the mass spectrometer on the appearance of these oxidative changes cannot be quantified easily, we decided to assay the role of the cysteines on the protein's redox effect. We covalently maleylated the cysteines using N-ethylmaleimide (NEM), which permanently prevents thiol groups from undergoing further redox chemistry (20)(21)(22). MS (Figs.…”

Section: Resultsmentioning

confidence: 99%

Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex

Orf

Saer

Niedzwiedzki

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Light-harvesting antenna complexes not only aid in the capture of solar energy for photosynthesis, but regulate the quantity of transferred energy as well. Light-harvesting regulation is important for protecting reaction center complexes from overexcitation, generation of reactive oxygen species, and metabolic overload. Usually, this regulation is controlled by the association of lightharvesting antennas with accessory quenchers such as carotenoids. One antenna complex, the Fenna-Matthews-Olson (FMO) antenna protein from green sulfur bacteria, completely lacks carotenoids and other known accessory quenchers. Nonetheless, the FMO protein is able to quench energy transfer in aerobic conditions effectively, indicating a previously unidentified type of regulatory mechanism. Through de novo sequencing MS, chemical modification, and mutagenesis, we have pinpointed the source of the quenching action to cysteine residues (Cys49 and Cys353) situated near two lowenergy bacteriochlorophylls in the FMO protein from Chlorobaculum tepidum. Removal of these cysteines (particularly removal of the completely conserved Cys353) through N-ethylmaleimide modification or mutagenesis to alanine abolishes the aerobic quenching effect. Electrochemical analysis and electron paramagnetic resonance spectra suggest that in aerobic conditions the cysteine thiols are converted to thiyl radicals which then are capable of quenching bacteriochlorophyll excited states through electron transfer photochemistry. This simple mechanism has implications for the design of bio-inspired light-harvesting antennas and the redesign of natural photosynthetic systems.photosynthesis | Fenna-Matthews-Olson protein | excitation quenching | thiyl radical | light-harvesting P hotosynthesis can be performed in the presence of oxygen (oxygenic photosynthesis, in which water is the electron source) or in its absence (anoxygenic photosynthesis, in which other reduced species such as sulfide are the electron sources) (1-3). Many bacteria performing anoxygenic photosynthesis contain type I reaction center (RC) protein complexes that use Fe-S clusters to transfer electrons to ferredoxin or related molecules after photoinduced charge separation (4-6). These Fe-S clusters are easily damaged by molecular oxygen. Therefore, anoxygenic phototrophs must use a pathway either to remove oxygen or to reduce the rate of photosynthesis whenever oxygen is encountered (1, 5).Phototrophic members of the bacterial phylum Chlorobi (green sulfur bacteria, GSBs) are anoxygenic phototrophs that contain such a type I RC. They also contain two peripheral antenna complexes that aid in regulating light absorption and energy transfer: the chlorosome and the homotrimeric Fenna-Matthews-Olson (FMO) protein complex. When oxygen is encountered, the bacteria are able to decrease the output of photosynthesis. This process involves creating trapping sites in the antenna complexes where de-excitation processes outcompete the rate of energy transfer to the RC, preventing RC damage. This process is well un...

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Section: Resultsmentioning

confidence: 99%

Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex

Orf

Saer

Niedzwiedzki

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Alhama et al [126] successfully determined the content of metallothionein (MT) in the digestive gland of clams from southern Spanish coastal sites with different metal levels by LC-FL. mBBr is classically used for the sensing of the cysteine residue in proteins [127,128]. Fan et al [128] used it for the SDS-PAGE electrophoretic profiling of thiol-rich phytochelatins (PCs) and MTs.…”

Section: Bimanesmentioning

confidence: 99%

Recent advances in separation and detection methods for thiol compounds in biological samples

Toyo’oka¹

2009

Journal of Chromatography B

157

109

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“…Among the possible blocking agents, NEM is more efficient than IAM or IAA because it completely blocks free thiols at a lower concentration [44]. Since IAA has a negative charge, it reacts with thiol more slowly than IAM [44].…”

Section: Extraction and Blockingmentioning

confidence: 99%

Thiol redox proteomics seen with fluorescent eyes: The detection of cysteine oxidative modifications by fluorescence derivatization and 2-DE

Izquierdo-Álvarez

Martínez‐Ruiz

2011

Journal of Proteomics

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Detection of reversible protein thiol modifications in tissues

Cited by 77 publications

References 34 publications

Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex

Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex

Recent advances in separation and detection methods for thiol compounds in biological samples

Thiol redox proteomics seen with fluorescent eyes: The detection of cysteine oxidative modifications by fluorescence derivatization and 2-DE

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