A Difference Infrared Study of Protein Structural Changes in the Photosynthetic Water-Oxidizing Complex

Steenhuis, Jacqueline J.; Barry, Bridgette A.

doi:10.1021/ja961691v

Cited by 21 publications

(102 citation statements)

References 51 publications

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“…3C, solid fill). Vibrational modes from the carbonyl groups of chlorophyll could make a contribution in this spectral region (31,40). However, 13 C labeling of MSP will not shift vibrational modes of pigments; this result supports the assignment to amino acid residues of MSP.…”

Section: Fig 2 Light-minus-dark Difference Ft-ir Spectra Obtained supporting

confidence: 67%

“…2A is compared with Fig. 2C, a variation in the ratio of the 1478 cm Ϫ1 line to broad spectral features between 1500 and 1200 cm Ϫ1 , previously assigned to S 2 -minus-S 1 (21,31,32,35), is observed. When PSII complexes in glycerol are illuminated at 200 K, the S 2 state is formed in the majority of centers, but Chl ϩ is oxidized in 33 Ϯ 9% of PSII centers (21).…”

Section: Controls For Ft-ir Studies Of the S 1 And S 2 States-inmentioning

confidence: 77%

“…2 (C and D). The difference FT-IR spectrum of the S 1 to S 2 transition is dominated by contributions from carboxylic acid and carboxylate groups close to or ligating to the manganese cluster (21,31,32). This assignment was based on group frequency arguments and on the lack of significant 15 N shifts upon global 15 N labeling (21).…”

Section: Controls For Ft-ir Studies Of the S 1 And S 2 States-inmentioning

confidence: 99%

“…The first is a frequency shift of the CϭO stretching vibration, perhaps due to a perturbation in the pK a or hydrogen bonding of these groups (see Ref. 31, and references therein). This first type of structural change would give rise to derivative-shaped spectral features in the isotope-edited spectrum, each of which would be accompanied by a 13 C-induced, downshifted, derivative-shaped line.…”

Section: Fig 2 Light-minus-dark Difference Ft-ir Spectra Obtained mentioning

confidence: 99%

“…The glycerol-containing sample (6 l) was placed on a 25-mm germanium window, concentrated under N 2 gas for 20 min at 4°C, and then sandwiched with a CaF 2 window (Harrick Scientific, Ossining, NY). The temperature control apparatus and illumination conditions, employing continuous illumination and a Dolan-Jenner annular illuminator, were described previously (21,31,32). The cryostat was equipped with two temperature sensors; the temperature sensor on the sample was continuously monitored through the use of LabView software.…”

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confidence: 99%

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Deprotonation of the 33-kDa, Extrinsic, Manganese-stabilizing Subunit Accompanies Photooxidation of Manganese in Photosystem II

Hutchison¹,

Steenhuis²,

Yocum³

et al. 1999

Journal of Biological Chemistry

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Photosystem II catalyzes photosynthetic water oxidation. The oxidation of water to molecular oxygen requires four sequential oxidations; the sequentially oxidized forms of the catalytic site are called the S states. An extrinsic subunit, the manganese-stabilizing protein (MSP), promotes the efficient turnover of the S states. MSP can be removed and rebound to the reaction center; removal and reconstitution is associated with a decrease in and then a restoration of enzymatic activity. We have isotopically edited MSP by uniform 13 C labeling of the Escherichia coli-expressed protein and have obtained the Fourier transform infrared spectrum associated with the S 1 to S 2 transition in the presence either of reconstituted 12 C or 13 C MSP. 13 C labeling of MSP is shown to cause 30 -60 cm ؊1 shifts in a subset of vibrational lines. The derived, isotope-edited vibrational spectrum is consistent with a deprotonation of glutamic/ aspartic acid residues on MSP during the S 1 to S 2 transition; the base, which accepts this proton(s), is not located on MSP. This finding suggests that this subunit plays a role as a stabilizer of a charged transition state and, perhaps, as a general acid/base catalyst of oxygen evolution. These results provide a molecular explanation for known MSP effects on oxygen evolution.In oxygenic photosynthesis, the multi-subunit protein complex, photosystem II (PSII), 1 uses light energy to oxidize water and to form molecular oxygen. Hydrophobic subunits, such as the D1 and D2 proteins, bind most of the prosthetic groups involved in charge separation. Water oxidation occurs at a catalytic site containing four manganese atoms. The catalytic site accumulates the four oxidizing equivalents required for water oxidation. The five sequentially oxidized states of the catalytic site are called the S states. Each oxidation of the catalytic site is associated with the reduction of quinone acceptor molecules, Q A , a single electron acceptor, and then Q B , a two-electron, two-proton acceptor (reviewed in Ref. 1).The 33-kDa, manganese-stabilizing protein (MSP) of PSII plays an important role in water oxidation (reviewed in Ref. 2). As an extrinsic subunit, MSP can be removed from the plant reaction center by several different types of biochemical treatments (3-6). MSP has also been removed by mutagenesis in the cyanobacterium, Synechocystis sp. PCC 6803 (7), and in a green algae, Chlamydomonas reinhardtii (8). In the presence of low concentrations of calcium and chloride, plant MSP was found to be required for photosynthetic oxygen evolution and for maintaining the stability of the manganese cluster (9, 10). In the presence of high concentrations of calcium and chloride, oxygen evolution occurs, but the steady state rate of enzymatic activity is impaired upon removal of MSP (7,9,(11)(12)(13)(14). In addition, removal of MSP and replacement with calcium and chloride result in kinetic inhibition of the S state transitions (12,(15)(16)(17)(18)(19). MSP can be rebound to PSII (20), and this reconstitution reverses ...

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Section: Fig 2 Light-minus-dark Difference Ft-ir Spectra Obtained supporting

confidence: 67%

Section: Controls For Ft-ir Studies Of the S 1 And S 2 States-inmentioning

confidence: 77%

Section: Controls For Ft-ir Studies Of the S 1 And S 2 States-inmentioning

confidence: 99%

Section: Fig 2 Light-minus-dark Difference Ft-ir Spectra Obtained mentioning

confidence: 99%

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confidence: 99%

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Deprotonation of the 33-kDa, Extrinsic, Manganese-stabilizing Subunit Accompanies Photooxidation of Manganese in Photosystem II

Hutchison¹,

Steenhuis²,

Yocum³

et al. 1999

Journal of Biological Chemistry

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Infrared spectroscopic identification of the C–O stretching vibration associated with the tyrosyl Z⋅ and D⋅ radicals in photosystem II1Supported by NIH GM 43272 (B.A.B.), NSF MCB 94-18164 (B.A.B.), a graduate minority fellowship from NIH GM 43273 (I.A.), a graduate fellowship from Committee on Institutional Cooperation, University of Minnesota (I.A.), and a summer research fellowship from Dupont, Central Research and Development, administered through the University of Minnesota (E.T.G.).1

Kim

Ayala

Steenhuis

et al. 1998

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Photosystem II (PSII) is a multisubunit complex, which catalyzes the photo-induced oxidation of water and reduction of plastoquinone. Difference Fourier-transform infrared (FT-IR) spectroscopy can be used to obtain information about the structural changes accompanying oxidation of the redox-active tyrosines, D and Z, in PSII. The focus of our work is the assignment of the 1478 cm-1 vibration, which is observable in difference infrared spectra associated with these tyrosyl radicals. The first set of FT-IR experiments is performed with continuous illumination. Use of cyanobacterial strains, in which isotopomers of tyrosine have been incorporated, supports the assignment of a positive 1478/1477 cm-1 mode to the C-O stretching vibration of the tyrosyl radicals. In negative controls, the intensity of this spectral feature decreases. The negative controls involve the use of inhibitors or site-directed mutants, in which the oxidation of Z or D is eliminated, respectively. The assignment of the 1478/1477 cm-1 mode is also based on control EPR and fluorescence measurements, which demonstrate that no detectable Fe+2QA- signal is generated under FT-IR experimental conditions. Additionally, the difference infrared spectrum, associated with formation of the S2QA- state, argues against the assignment of the positive 1478 cm-1 line to the C-O vibration of QA-. In the second set of FT-IR experiments, single turnover flashes are employed, and infrared difference spectra are recorded as a function of time after photoexcitation. Comparison to kinetic transients generated in control EPR experiments shows that the decay of the 1477 cm-1 line precisely parallels the decay of the D. EPR signal. Taken together, these two experimental approaches strongly support the assignment of a component of the 1478/1477 cm-1 vibrational lines to the C-O stretching modes of tyrosyl radicals in PSII. Possible reasons for the apparently contradictory results of Hienerwadel et al. (1996) Biochemistry 35, 15,447-15,460 and Hienerwadel et al. (1997) Biochemistry 36, 14,705-14,711 are discussed. Copyright 1998 Elsevier Science B.V. All rights reserved.

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Infrared spectroscopic identification of the C–O stretching vibration associated with the tyrosyl Z⋅ and D⋅ radicals in photosystem II2Supported by NIH GM 43272 (B.A.B.), NSF MCB 94-18164 (B.A.B.), a graduate minority supplement to NIH GM 43273 (I.A.), a graduate fellowship from Committee on Institutional Cooperation, University of Minnesota (I.A.), and a summer research fellowship from Dupont, Central Research and Development, administered through the University of Minnesota (E.T.G.).2

Kim

Ayala

Steenhuis

et al. 1998

Biochimica et Biophysica Acta (BBA) - Bioenergetics

View full text Add to dashboard Cite

A Difference Infrared Study of Protein Structural Changes in the Photosynthetic Water-Oxidizing Complex

Cited by 21 publications

References 51 publications

Deprotonation of the 33-kDa, Extrinsic, Manganese-stabilizing Subunit Accompanies Photooxidation of Manganese in Photosystem II

Deprotonation of the 33-kDa, Extrinsic, Manganese-stabilizing Subunit Accompanies Photooxidation of Manganese in Photosystem II

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