The Role of Tyrosine M210 in the Initial Charge Separation in the Reaction Center of Rhodobacter sphaeroides

Gray, Kevin A.; Farchaus, J. W.; Wachtveitl, Josef; Breton, Jacques; Finkele, Ulrich; Lauterwasser, Christoph; Oesterhelt, Dieter

doi:10.1007/978-3-642-61297-8_25

Cited by 4 publications

(5 citation statements)

References 38 publications

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“…This corroborates results obtained with [3-vinyl]-analogucs of BChl a and BPhe a [19,20] which also exchange selectively into the BA, u and HA, B binding sites, respectively [20]. It is also corroborated by mutagcnctic studies [10][11][12][13][14][15][16] and by the unusual pigment composition of Chloroflertts attrantiactts RC [30][31][32]. The stability and the spectroscopic properties of the complexes into which the 3Lhydroxy analogues are introduced are in contradiction to the common interpretation that borohydride treatment leads to chemical reduction of BChl a bound to B~ at C-3', and its subsequent loss from the reaction center.…”

Section: Spectrasupporting

confidence: 87%

See 1 more Smart Citation

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Struck¹,

Müller²,

Scheer³

1991

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Pigments of borohydride-treated reaction centers of Rhodobacter sphaeroides R 26 and Rhodopseudomonas viridiswere analyzed by HPLC with polychromatie detection. In both species, pigment composition and contents were unchanged. Reaction centers from Rhodobacter sphaeroides R26 were prepared in which bacteriochlorophylls (B A B) and bacteriopheophytins (HA, n) were exchanged with their potential borohydride products reduced at C-3 t.[3-Hydroxyethyl]-BChl a exchanges selectively into the BA, B pockets, and 31-OH-BPh a to the HA, B pockets. Stable reaction centers are obtained in both cases. A comparison of the absorption and circular dichroism spectra of reaction centers after exchange with 31-OH pigments, and of borohydride-modified reaction centers, reveal distinct differences. It is concluded that during borohydride reduction none of the pigments is chemically modified or extracted from the reaction centers.

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Section: Spectrasupporting

confidence: 87%

“…Today there are several possibilities available to modify either the amino-acid [10][11][12][13][14][15][16] and/or the pigment composition [17][18][19][20]. Historically, however, treatment with borohydride was the first method by which reaction centers from Rb.…”

Section: Introductionmentioning

confidence: 99%

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Struck¹,

Müller²,

Scheer³

1991

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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“…Much work supports the model that the native Tyr at M210 lowers the free energy of the charge‐separated state

P^{+} {normalB}_{A}^{-}

, while a Phe at L181 on the B side provides no parallel effect on the free energy of

P^{+} {normalB}_{B}^{-}

(Fig. C; ). Reversal of this asymmetry hinders ET to the A side (M210‘F’) and promotes ET to the B side (L181‘Y’) .…”

Section: Rationale For Choice Of Substitutions Employedmentioning

confidence: 64%

Species differences in unlocking B‐side electron transfer in bacterial reaction centers

et al. 2016

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The structure of the bacterial photosynthetic reaction center (RC) reveals symmetry-related electron transfer (ET) pathways, but only one path is used in native RCs. Analogous mutations have been made in two Rhodobacter (R.) species. A glutamic acid at position 133 in the M subunit increases transmembrane charge separation via the naturally inactive (B-side) path through impacts on primary ET in mutant R. sphaeroides RCs. Prior work showed that the analogous substitution in the R. capsulatus RC also increases B-side activity, but mainly affects secondary ET. The overall yields of transmembrane ET are similar, but enabled in fundamentally different ways.

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“…In addition to this purely structural role, it is probable that the protein plays some specific function in assisting the electron transport and in preventing wasteful back reactions. Aromatic residues such as Tyr M208 located between P, B A , and H A or Trp M250 situated in van der Waals contact distance of both H A and Q A ( 9 ; Figure ) have been pinpointed as playing a key role in the electron-transfer reactions ( − ). Structural rearrangements of the cofactors and of the RC protein are expected to contribute to the reorganization energy associated with long-range electron transfer.…”

mentioning

confidence: 99%

Conformational Heterogeneity of the Bacteriopheophytin Electron Acceptor H_A in Reaction Centers from Rhodopseudomonas viridis Revealed by Fourier Transform Infrared Spectroscopy and Site-Directed Mutagenesis

et al. 1999

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The light-induced Fourier transform infrared (FTIR) difference spectra corresponding to the photoreduction of either the HA bacteriopheophytin electron acceptor (HA-/HA spectrum) or the QA primary quinone (QA-/QA spectrum) in photosynthetic reaction centers (RCs) of Rhodopseudomonas viridis are reported. These spectra have been compared for wild-type (WT) RCs and for two site-directed mutants in which the proposed interactions between the carbonyls on ring V of HA and the RC protein have been altered. In the mutant EQ(L104), the putative hydrogen bond between the protein and the 9-keto C=O of HA should be affected by changing Glu L104 to a Gln. In the mutant WF(M250), the van der Waals interactions between Trp M250 and the 10a-ester C=O of HA should be modified. The characteristic effects of both mutations on the FTIR spectra support the proposed interactions and allow the IR modes of the 9-keto and 10a-ester C=O of HA and HA- to be assigned. Comparison of the HA-/HA and QA-/QA spectra leads us to conclude that the QA-/QA IR signals in the spectral range above 1700 cm-1 are largely dominated by contributions from the electrostatic response of the 10a-ester C=O mode of HA upon QA photoreduction. A heterogeneity in the conformation of the 10a-ester C=O mode of HA in WT RCs, leading to three distinct populations of HA, appears to be related to differences in the hydrogen-bonding interactions between the carbonyls of ring V of HA and the RC protein. The possibility that this structural heterogeneity is related to the observed multiexponential kinetics of electron transfer and the implications for primary processes are discussed. The effect of 1H/2H exchange on the QA-/QA spectra of the WT and mutant RCs shows that neither Glu L104 nor any other exchangeable carboxylic residue changes appreciably its protonation state upon QA reduction.

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The Role of Tyrosine M210 in the Initial Charge Separation in the Reaction Center of Rhodobacter sphaeroides

Abstract: This work is subjeet to Copyright. All rights are reserved, whether the vvhole or part ol'thc malcrial is conccrncd,spccifically the rights oftranslation,reprinting,rc-usc ofillustrations, recilation, broaclcasiing, reproduetion on microfilms or in oihcr ways, and storage in data banks.

Cited by 4 publications

References 38 publications

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Species differences in unlocking B‐side electron transfer in bacterial reaction centers

Conformational Heterogeneity of the Bacteriopheophytin Electron Acceptor H_A in Reaction Centers from Rhodopseudomonas viridis Revealed by Fourier Transform Infrared Spectroscopy and Site-Directed Mutagenesis

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The Role of Tyrosine M210 in the Initial Charge Separation in the Reaction Center of Rhodobacter sphaeroides

Abstract: This work is subjeet to Copyright. All rights are reserved, whether the vvhole or part ol'thc malcrial is conccrncd,spccifically the rights oftranslation,reprinting,rc-usc ofillustrations, recilation, broaclcasiing, reproduetion on microfilms or in oihcr ways, and storage in data banks.

Cited by 4 publications

References 38 publications

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Modified bacterial reaction centers. 4. The borohydride treatment reinvestigated: comparison with selective exchange experiments at binding sites BA,B and HA,B

Species differences in unlocking B‐side electron transfer in bacterial reaction centers

Conformational Heterogeneity of the Bacteriopheophytin Electron Acceptor HA in Reaction Centers from Rhodopseudomonas viridis Revealed by Fourier Transform Infrared Spectroscopy and Site-Directed Mutagenesis

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Conformational Heterogeneity of the Bacteriopheophytin Electron Acceptor H_A in Reaction Centers from Rhodopseudomonas viridis Revealed by Fourier Transform Infrared Spectroscopy and Site-Directed Mutagenesis