Photodynamic and Radiolytic Inactivation of Ion Channels Formed by Gramicidin A: Oxidation and Fragmentation

Kunz, Lars; Zeidler, U.; Haegele, K. D.; Przybylski, Michael; Stark, G.

doi:10.1021/bi00037a030

Cited by 50 publications

(29 citation statements)

References 41 publications

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“…The adjacent residue Arg-69 has been reported to be involved in chlorophyll binding in Lhcb1 by neutralization of Asp und Glu residues through ionic interaction [48]. Thus, oxidation of Trp-70 [49] might influence protein-chlorophyll binding and lead to conformational changes in the organization of LHCII. In addition to the fragment (70-86), several other sites in the LHCII proteins were found modified by oxidation, of which the oxidation of Met residues may have occurred in-gel, in agreement with the identification of the nonoxidized form in Lhcb proteins.…”

Section: Discussionmentioning

confidence: 99%

Structure and dynamics of photosystem II light-harvesting complex revealed by high-resolution FTICR mass spectrometric proteome analysis

Galetskiy

Susnea

Reiser

et al. 2008

J. Am. Soc. Mass Spectrom.

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Structure and dynamics of membrane-bound light-harvesting pigment-protein complexes (LHCs), which collect and transmit light energy for photosynthesis and thereby play an essential role in the regulation of photosynthesis and photoprotection, were identified and characterized using high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). LHCs from photosystem n (LHCn) were isolated from the thylakoid membrane of Arabidopsis thaliana leaves after light stress treatment using sucrose density gradient centrifugation, and separated by gel-filtration into LHCn subcomplexes. Using reversed-phase high-performance liquid chromatography and two-dimensional (2D) gel electrophoresis, the LHCn proteins, Lhcbl-6 and fibrillins, were efficiently separated and identified by FIICR-MS. Some of the LHcn subcomplexes were shown to migrate from photosystem n to photosystem I as a result of short-term adaptation to changes in light intensity. In the mobile LHCn subcomplexes, decreased levels of fibrillins and a modified composition of LHCn protein isoforms were identified compared to the tightly bound LHcn subcomplexes. In addition, FTICR-MS analysis revealed several oxidative modifications of LHCn proteins. A number of protein spots in 2D gels were found to contain a mixture of proteins, illustrating the feasibility of high-resolution mass spectrometry to identify proteins that remain unseparated in 2D gels even upon extended pH gradients. (J

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Section: Discussionmentioning

confidence: 99%

Structure and dynamics of photosystem II light-harvesting complex revealed by high-resolution FTICR mass spectrometric proteome analysis

Galetskiy

Susnea

Reiser

et al. 2008

J. Am. Soc. Mass Spectrom.

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“…To monitor this efficacy, we chose the method of sensitized photoinactivation of gramicidin channels in BLM (9). It was shown previously (9,10,14,15) that the channel photoinactivation results from the interaction of reactive oxygen species generated upon excitation of a photosensitizer (16) with tryp-tophan residues of gramicidin. According to the literature (17,18) the tryptophans residing at the water-membrane interface are critical for maintaining the gramicidin channel structure as the transmembrane head-to-head dimer (19)(20)(21).…”

Section: Discussionmentioning

confidence: 99%

Effect of Fluoride Anions on Gramicidin Photoinactivation Sensitized by Sulfonated Aluminum Phthalocyanines¶

Шаповалов¹,

Rokitskaya²,

Kotova³

et al. 2001

Photochem Photobiol

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Interaction of potent photodynamic agents, sulfonated aluminum phthalocyanines (AlPcSn where n is a number of sulfonic groups), with biological membranes was studied here using model systems: sensitized photoinactivation of gramicidin channels in planar lipid bilayers and adsorption on lipid monolayers. Fluoride anions known to form complexes with aluminum were found to inhibit both the adsorption of aluminum phthalocyanines on lipid monolayers, as measured with a Langmuir trough by surface pressure and surface potential changes, and photodynamic efficacy of the dyes, as studied by gramicidin channel photoinactivation. The similar effects were caused by the alkalinization of the medium. Fluoride anions appeared to be much more effective in the case of AlPcS4 as compared to AlPcS3. The suppression of the photodynamic potency of aluminum phthalocyanines was attributed to desorption of the dyes from lipid bilayers induced by fluoride or hydroxyl ions. With AlPcS4 an enhancement of the dye aggregation leading to a decrease in the sensitizing activity was probably involved in the fluoride effect as revealed by absorption and fluorescence spectral measurements. Capillary electrophoresis was employed to understand the mechanism of the dye desorption. The results of these experiments indicated that the reduction in the membrane affinity was associated with an increase in the negative charge of the dye molecules due to the binding of fluoride or hydroxyl ions.

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“…following protein separation by gel electrophoresis (5). Trp modification to NFK and KYN and degradation have been described in mitochondrial proteins associated with redox metabolism (6, 7) in human cataract lenses (8, 9), and upon photolytic oxidation (10). Modified proteins have been proposed as markers of oxidative stress, e.g.…”

Section: Introductionmentioning

confidence: 99%

Mass spectrometric identification of oxidative modifications of tryptophan residues in proteins: Chemical artifact or post-translational modification?

Perdivara

Deterding

Przybylski

et al. 2010

J. Am. Soc. Mass Spectrom.

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Oxidative modification of tryptophan to kynurenine (KYN) and N-formyl kynurenine (NFK) has been described in mitochondrial proteins associated with redox metabolism, and in human cataract lenses. To a large extent, however, previously reported identifications of these modifications were performed using peptide mass fingerprinting and/or tandem-MS data of proteins separated by gel electrophoresis. To date, it is uncertain whether NFK and KYN may represent sample handling artifacts or exclusively post-translational events. To address the problem of the origin of tryptophan oxidation, we characterized several antibodies by liquid chromatography-tandem mass spectrometry, with and without the use of electrophoretic separation of heavy and light chains. Antibodies are not normally expected to undergo oxidative modifications, however, several tryptophan (Trp) residues on both heavy and light chains were found extensively modified to both doubly oxidized Trp and KYN following SDS-PAGE separation and in-gel digestion. In contrast, those residues were observed as non-modified upon in-solution digestion. These results indicate that Trp oxidation may occur as an artifact in proteins separated by SDS-PAGE, and their presence should be carefully interpreted, especially when gel electrophoretic separation methods are employed. (J Am Soc

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Photodynamic and Radiolytic Inactivation of Ion Channels Formed by Gramicidin A: Oxidation and Fragmentation

Cited by 50 publications

References 41 publications

Structure and dynamics of photosystem II light-harvesting complex revealed by high-resolution FTICR mass spectrometric proteome analysis

Structure and dynamics of photosystem II light-harvesting complex revealed by high-resolution FTICR mass spectrometric proteome analysis

Effect of Fluoride Anions on Gramicidin Photoinactivation Sensitized by Sulfonated Aluminum Phthalocyanines¶

Mass spectrometric identification of oxidative modifications of tryptophan residues in proteins: Chemical artifact or post-translational modification?

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