High yield of secondary B-side electron transfer in mutant Rhodobacter capsulatus reaction centers

Kressel, Lucas; Faries, Kaitlyn M.; Wander, Marc J.; Zogzas, Charles E.; Mejdrich, Rachel J.; Hanson, Deborah K.; Holten, Dewey; Laible, Philip D.; Kirmaier, Christine

doi:10.1016/j.bbabio.2014.07.015

Cited by 11 publications

(16 citation statements)

References 62 publications

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“…Consistent with previous findings for the V(M131)E mutation in R. capsulatus , the Q x bleach of H B shows a shift to longer wavelength in R. sphaeroides RCs carrying the T(M133)E mutation (to ~535 nm from ~527 nm; Figs , and Table ) when compared to RCs with the native residue. Spectral shifts of the H B anion (transient absorption of

H_{normalB}^{-}

) attributable to the T(M133)E mutation are also resolved.…”

Section: Resultssupporting

confidence: 91%

“…

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

yields obtained for R. sphaeroides (panel A) and R. capsulatus (panel B and ) mutant RC s (as compared to WT ) following a 7‐ns, 532‐nm excitation flash utilized by the millisecond screening assay . Filled, blue bars represent mutants with the F(L181)X+ FHV background.…”

Section: Resultsmentioning

confidence: 99%

“…Ground‐state spectra, millisecond (ms) screening assays, ultrafast transient absorption (TA) experiments, and measurements of Q B site occupancy followed procedures reported earlier . Specifically, a 100‐fs, 1 kHz laser system (Spectra Physics, Santa Clara, CA, USA) with Helios or EOS spectrometers (Ultrafast Systems, Sarasota, FL, USA) were used for TA experiments.…”

Section: Methodsmentioning

confidence: 99%

“…RCs from R. capsulatus have continued to lead discovery of the delicate balance of protein‐cofactor interactions that can support ET via the B‐side path. As a means to identify variants that are competent in the reduction of Q B via sole activity of the B‐side ET cofactors, streamlined mutagenesis and protein purification strategies have been developed .…”

Section: Rationale For Choice Of Substitutions Employedmentioning

confidence: 99%

“…Previous work has shown that Asp or Glu substituted at M133/M131 can form a hydrogen bond with H B , promoting its reduction. The combination of the V(M131)E (‘E’) substitution with the ‘core’ FHV and YFHV mutations in the R. capsulatus RC has resulted in large increases in yields of B‐side ET .…”

Section: Rationale For Choice Of Substitutions Employedmentioning

confidence: 99%

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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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H_{normalB}^{-}

) attributable to the T(M133)E mutation are also resolved.…”

Section: Resultssupporting

confidence: 91%

“…

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

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Rationale For Choice Of Substitutions Employedmentioning

confidence: 99%

Section: Rationale For Choice Of Substitutions Employedmentioning

confidence: 99%

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

et al. 2016

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Consequences of saturation mutagenesis of the protein ligand to the B-side monomeric bacteriochlorophyll in reaction centers from Rhodobacter capsulatus

et al. 2019

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Design of dinuclear manganese cofactors for bacterial reaction centers

Olson

Espiritu

Edwardraja

et al. 2016

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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A compelling target for the design of electron transfer proteins with novel cofactors is to create a model for the oxygen-evolving complex, a Mn4Ca cluster, of photosystem II. A mononuclear Mn cofactor can be added to the bacterial reaction center, but the addition of multiple metal centers is constrained by the native protein architecture. Alternatively, metal centers can be incorporated into artificial proteins. Designs for the addition of dinuclear metal centers to four-helix bundles resulted in three artificial proteins with ligands for one, two, or three dinuclear metal centers able to bind Mn. The three-dimensional structure determined by X-ray crystallography of one of the Mn-proteins confirmed the design features and revealed details concerning coordination of the Mn center. Electron transfer between these artificial Mn-proteins and bacterial reaction centers was investigated using optical spectroscopy. After formation of a light-induced, charge-separated state, the experiments showed that the Mn-proteins can donate an electron to the oxidized bacteriochlorophyll dimer of modified reaction centers, with the Mn-proteins having additional metal centers being more effective at this electron transfer reaction. Modeling of the structure of the Mn-protein docked to the reaction center showed that the artificial protein likely binds on the periplasmic surface similarly to cytochrome c2, the natural secondary donor. Combining reaction centers with exogenous artificial proteins provides the opportunity to create ligands and investigate the influence of inhomogeneous protein environments on multinuclear redox-active metal centers. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.

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High yield of secondary B-side electron transfer in mutant Rhodobacter capsulatus reaction centers

Cited by 11 publications

References 62 publications

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

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

Consequences of saturation mutagenesis of the protein ligand to the B-side monomeric bacteriochlorophyll in reaction centers from Rhodobacter capsulatus

Design of dinuclear manganese cofactors for bacterial reaction centers

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