Detecting transient protein–protein interactions by X‐ray absorption spectroscopy: The cytochrome <i>c</i><sub>6</sub>‐photosystem I complex

Dı́az-Moreno, Irene; Díaz-Quintana, Antonio; Subı́as, G.; Mairs, Trevor; Rosa, Miguel Á. De la; Díaz‐Moreno, Sofía

doi:10.1016/j.febslet.2006.04.045

Cited by 11 publications

(13 citation statements)

References 26 publications

(36 reference statements)

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“…As the reducing electron is not located in these orbitals, such subtle changes may have little influence on the redox potential. This situation is clearly different to that previously reported for cytochrome c 6 , which shows a perturbation on the pre-edge region corresponding to its oxidized species, instead of the reduced ones, upon binding its reaction partner, photosystem I (Díaz-Moreno et al 2006). In such case the pre-edge corresponds to transfer to a half-occupied non-bonding d orbital, which is that receiving the reducing electron, so the observed changes can be correlated with changes in the redox potential of the heme protein.…”

Section: Resultscontrasting

confidence: 99%

“…1 eV below that of C f III , as previously found for the reduced and oxidized states of two closely related proteins, as heart cytochrome c (Cheng et al 1999) and Nostoc cytochrome c 6 (Díaz-Moreno et al 2006). In case of cytochrome c (Cheng et al 1999), photoreduction of the oxidized species was observed only after the 16th spectrum of the series.…”

Section: Resultssupporting

confidence: 77%

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The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

et al. 2006

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The transient complex between cytochrome f and plastocyanin from the cyanobacterium Nostoc sp. PCC 7119 has been analysed by X-ray Absorption Spectroscopy in solution, using both proteins in their oxidized and reduced states. Fe K-edge data mainly shows that the atypical metal coordination geometry of cytochrome f, in which the N-terminal amino acid acts as an axial ligand of the heme group, remains unaltered upon binding to its redox partner, plastocyanin. This fact suggests that cytochrome f provides a stable binding site for plastocyanin and minimizes the reorganization energy required in the transient complex formation, which could facilitate the electron transfer between the two redox partners.Keywords Cytochrome f AE Electron transfer AE Metalloproteins AE Plastocyanin AE Transient complexes AE X-ray absorption spectroscopy Abbreviations Cf water-soluble fragment of cytochrome f ET electron transfer EXAFS extended X-ray absorption fine structure FT Fourier transform Pc plastocyanin XANES X-ray absorption near edge structure XAS X-ray absorption spectroscopy XRD X-Ray diffraction DE 0 internal potential correction Dr change in the distance between the metal and ligand atoms r Debye-Waller parameter related to the system dynamic disorder

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Section: Resultscontrasting

confidence: 99%

Section: Resultssupporting

confidence: 77%

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

et al. 2006

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“…For comparison with biomolecules we add Fe 2p and N 1s spectra for cytochrome c, a metalloprotein that plays a role in reducing photo-oxidized donors in lipid membranes. 12,23 To our knowledge only the much broader Fe 1s edge has been reported for cytochrome c. [51][52][53][54][55] While fingerprinting methods provide quick information about the oxidation state from the raw data, there is a lot more to be learned from proper theoretical modeling, as discussed in Sec. II B.…”

Section: Transition Metal 2p Edgesmentioning

confidence: 97%

X-ray absorption spectroscopy of biomimetic dye molecules for solar cells

Cook

Liu

Yang

et al. 2009

The Journal of Chemical Physics

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Dye-sensitized solar cells are potentially inexpensive alternatives to traditional semiconductor solar cells. In order to optimize dyes for solar cells we systematically investigate the electronic structure of a variety of porphyrins and phthalocyanines. As a biological model system we use the heme group in cytochrome c which plays a role in biological charge transfer processes. X-ray absorption spectroscopy of the N 1s and C 1s edges reveals the unoccupied molecular orbitals and the orientation of the molecules in thin films. The transition metal 2p edges reflect the oxidation state of the central metal atom, its spin state, and the ligand field of the surrounding N atoms. The latter allows tuning of the energy position of the lowest unoccupied orbital by several tenths of an eV by tailoring the molecules and their deposition. Fe and Mn containing phthalocyanines oxidize easily from +2 to +3 in air and require vacuum deposition for obtaining a reproducible oxidation state. Chlorinated porphyrins, on the other hand, are reduced from +3 to +2 during vacuum deposition at elevated temperatures. These findings stress the importance of controlled thin film deposition for obtaining photovoltaic devices with an optimum match between the energy levels of the dye and those of the donor and acceptor electrodes, together with a molecular orientation for optimal overlap between the pi orbitals in the direction of the carrier transport.

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“…Likewise, metal ions can mediate or trigger protein–protein interactions, as already pointed out [28]. In redox proteins, however, minor changes in the metal environment are associated with transient binding, although, in some cases, they could play a physiological role [34,35].…”

Section: Interactions Involving Metalloproteinsmentioning

confidence: 99%

Proteomic tools for the analysis of transient interactions between metalloproteins

et al. 2011

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Metalloproteins play major roles in cell metabolism and signalling pathways. In many cases, they show moonlighting behaviour, acting in different processes, depending on the physiological state of the cell. To understand these multitasking proteins, we need to discover the partners with which they carry out such novel functions. Although many technological and methodological tools have recently been reported for the detection of protein interactions, specific approaches to studying the interactions involving metalloproteins are not yet well developed. The task is even more challenging for metalloproteins, because they often form short‐lived complexes that are difficult to detect. In this review, we gather the different proteomic techniques and biointeractomic tools reported in the literature. All of them have shown their applicability to the study of transient and weak protein–protein interactions, and are therefore suitable for metalloprotein interactions.

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Detecting transient protein–protein interactions by X‐ray absorption spectroscopy: The cytochrome c₆‐photosystem I complex

Cited by 11 publications

References 26 publications

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

X-ray absorption spectroscopy of biomimetic dye molecules for solar cells

Proteomic tools for the analysis of transient interactions between metalloproteins

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Detecting transient protein–protein interactions by X‐ray absorption spectroscopy: The cytochrome c6‐photosystem I complex

Cited by 11 publications

References 26 publications

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

X-ray absorption spectroscopy of biomimetic dye molecules for solar cells

Proteomic tools for the analysis of transient interactions between metalloproteins

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Product

Resources

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Detecting transient protein–protein interactions by X‐ray absorption spectroscopy: The cytochrome c₆‐photosystem I complex