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Oxidized amino acid residues in the vicinity of Q(A) and Pheo(D1) of the photosystem II reaction center: putative generation sites of reducing-side reactive oxygen species.

Frankel LK, Sallans L, Limbach PA, Bricker TM - PLoS ONE (2013)

Bottom Line: A number of different sites including the Mn4O5Ca cluster, P680, PheoD1, QA, QB and cytochrome b559 have been hypothesized to produce reactive oxygen species in the photosystem.In this communication using Fourier-transform ion cyclotron resonance mass spectrometry we have identified several residues on the D1 and D2 proteins from spinach which are oxidatively modified and in close proximity to QA (D1 residues (239)F, (241)Q, (242)E and the D2 residues (238)P, (239)T, (242)E and (247)M) and PheoD1 (D1 residues (130)E, (133)L and (135)F).These residues may be associated with reactive oxygen species exit pathways located on the reducing side of the photosystem, and their modification may indicate that both QA and PheoD1 are sources of reactive oxygen species on the reducing side of Photosystem II.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
Under a variety of stress conditions, Photosystem II produces reactive oxygen species on both the reducing and oxidizing sides of the photosystem. A number of different sites including the Mn4O5Ca cluster, P680, PheoD1, QA, QB and cytochrome b559 have been hypothesized to produce reactive oxygen species in the photosystem. In this communication using Fourier-transform ion cyclotron resonance mass spectrometry we have identified several residues on the D1 and D2 proteins from spinach which are oxidatively modified and in close proximity to QA (D1 residues (239)F, (241)Q, (242)E and the D2 residues (238)P, (239)T, (242)E and (247)M) and PheoD1 (D1 residues (130)E, (133)L and (135)F). These residues may be associated with reactive oxygen species exit pathways located on the reducing side of the photosystem, and their modification may indicate that both QA and PheoD1 are sources of reactive oxygen species on the reducing side of Photosystem II.

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Oxidized Residues Identified on the Stromally Exposed Regions of the D1 and D2 Proteins in the Vicinity of QA and PheoD1.The T. vulcanus residues corresponding to the oxidatively modified spinach residues (Table 1) are highlighted. These oxidized residues are shown as spheres superimposed on monomer I of the T. vulcanus structure. For clarity, only the D1 and D2 proteins and their associated cofactors are shown. A. the view from outside Monomer I, looking towards the dimeric complex from within the plane of the membrane. B. the view from Monomer II looking towards its interface with Monomer I within the plane of the membrane. The D1 protein is shown in pale green and the D2 protein is shown in pale yellow. The oxidatively modified residues of D1 are shown in dark green while those of D2 are shown in orange. Various cofactors of both D1 and D2 are labeled and colored pale green or yellow, respectively. PheoD1 is shown in bright green. The non-heme iron is shown in bright red. The Mn4O5Ca cluster and its associated chloride ions are labeled as the OEC. Figs. 2–4 were produced using PYMOL [53].
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pone-0058042-g002: Oxidized Residues Identified on the Stromally Exposed Regions of the D1 and D2 Proteins in the Vicinity of QA and PheoD1.The T. vulcanus residues corresponding to the oxidatively modified spinach residues (Table 1) are highlighted. These oxidized residues are shown as spheres superimposed on monomer I of the T. vulcanus structure. For clarity, only the D1 and D2 proteins and their associated cofactors are shown. A. the view from outside Monomer I, looking towards the dimeric complex from within the plane of the membrane. B. the view from Monomer II looking towards its interface with Monomer I within the plane of the membrane. The D1 protein is shown in pale green and the D2 protein is shown in pale yellow. The oxidatively modified residues of D1 are shown in dark green while those of D2 are shown in orange. Various cofactors of both D1 and D2 are labeled and colored pale green or yellow, respectively. PheoD1 is shown in bright green. The non-heme iron is shown in bright red. The Mn4O5Ca cluster and its associated chloride ions are labeled as the OEC. Figs. 2–4 were produced using PYMOL [53].

Mentions: The D1 and D2 proteins are highly homologous between higher plants and cyanobacteria (>95% similarity). Consequently, we can directly map the modified residues observed to be modified in spinach onto the homologous residues in the T. vulcanus crystal structure. These results are shown in Fig. 2. The close proximity of oxidatively modified residues to QA and PheoD1 is evident in this illustration. Additionally, it is apparent that these residues appear to form two rather distinct groups. The first group appears associated with QA, consists of both D1 and D2 residues, and leads in a nearly continuous manner from the cofactor to the surface of the complex. The second group is associated with PheoD1, consists solely of D1 residues, also forming a near continuous grouping of modified residues. This group of residues, however, does not reach the surface of the PS II complex.


Oxidized amino acid residues in the vicinity of Q(A) and Pheo(D1) of the photosystem II reaction center: putative generation sites of reducing-side reactive oxygen species.

Frankel LK, Sallans L, Limbach PA, Bricker TM - PLoS ONE (2013)

Oxidized Residues Identified on the Stromally Exposed Regions of the D1 and D2 Proteins in the Vicinity of QA and PheoD1.The T. vulcanus residues corresponding to the oxidatively modified spinach residues (Table 1) are highlighted. These oxidized residues are shown as spheres superimposed on monomer I of the T. vulcanus structure. For clarity, only the D1 and D2 proteins and their associated cofactors are shown. A. the view from outside Monomer I, looking towards the dimeric complex from within the plane of the membrane. B. the view from Monomer II looking towards its interface with Monomer I within the plane of the membrane. The D1 protein is shown in pale green and the D2 protein is shown in pale yellow. The oxidatively modified residues of D1 are shown in dark green while those of D2 are shown in orange. Various cofactors of both D1 and D2 are labeled and colored pale green or yellow, respectively. PheoD1 is shown in bright green. The non-heme iron is shown in bright red. The Mn4O5Ca cluster and its associated chloride ions are labeled as the OEC. Figs. 2–4 were produced using PYMOL [53].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585169&req=5

pone-0058042-g002: Oxidized Residues Identified on the Stromally Exposed Regions of the D1 and D2 Proteins in the Vicinity of QA and PheoD1.The T. vulcanus residues corresponding to the oxidatively modified spinach residues (Table 1) are highlighted. These oxidized residues are shown as spheres superimposed on monomer I of the T. vulcanus structure. For clarity, only the D1 and D2 proteins and their associated cofactors are shown. A. the view from outside Monomer I, looking towards the dimeric complex from within the plane of the membrane. B. the view from Monomer II looking towards its interface with Monomer I within the plane of the membrane. The D1 protein is shown in pale green and the D2 protein is shown in pale yellow. The oxidatively modified residues of D1 are shown in dark green while those of D2 are shown in orange. Various cofactors of both D1 and D2 are labeled and colored pale green or yellow, respectively. PheoD1 is shown in bright green. The non-heme iron is shown in bright red. The Mn4O5Ca cluster and its associated chloride ions are labeled as the OEC. Figs. 2–4 were produced using PYMOL [53].
Mentions: The D1 and D2 proteins are highly homologous between higher plants and cyanobacteria (>95% similarity). Consequently, we can directly map the modified residues observed to be modified in spinach onto the homologous residues in the T. vulcanus crystal structure. These results are shown in Fig. 2. The close proximity of oxidatively modified residues to QA and PheoD1 is evident in this illustration. Additionally, it is apparent that these residues appear to form two rather distinct groups. The first group appears associated with QA, consists of both D1 and D2 residues, and leads in a nearly continuous manner from the cofactor to the surface of the complex. The second group is associated with PheoD1, consists solely of D1 residues, also forming a near continuous grouping of modified residues. This group of residues, however, does not reach the surface of the PS II complex.

Bottom Line: A number of different sites including the Mn4O5Ca cluster, P680, PheoD1, QA, QB and cytochrome b559 have been hypothesized to produce reactive oxygen species in the photosystem.In this communication using Fourier-transform ion cyclotron resonance mass spectrometry we have identified several residues on the D1 and D2 proteins from spinach which are oxidatively modified and in close proximity to QA (D1 residues (239)F, (241)Q, (242)E and the D2 residues (238)P, (239)T, (242)E and (247)M) and PheoD1 (D1 residues (130)E, (133)L and (135)F).These residues may be associated with reactive oxygen species exit pathways located on the reducing side of the photosystem, and their modification may indicate that both QA and PheoD1 are sources of reactive oxygen species on the reducing side of Photosystem II.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
Under a variety of stress conditions, Photosystem II produces reactive oxygen species on both the reducing and oxidizing sides of the photosystem. A number of different sites including the Mn4O5Ca cluster, P680, PheoD1, QA, QB and cytochrome b559 have been hypothesized to produce reactive oxygen species in the photosystem. In this communication using Fourier-transform ion cyclotron resonance mass spectrometry we have identified several residues on the D1 and D2 proteins from spinach which are oxidatively modified and in close proximity to QA (D1 residues (239)F, (241)Q, (242)E and the D2 residues (238)P, (239)T, (242)E and (247)M) and PheoD1 (D1 residues (130)E, (133)L and (135)F). These residues may be associated with reactive oxygen species exit pathways located on the reducing side of the photosystem, and their modification may indicate that both QA and PheoD1 are sources of reactive oxygen species on the reducing side of Photosystem II.

Show MeSH
Related in: MedlinePlus