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Hervás, Manuel; Navarro, José A.; Molina-Heredia, Fernando P.; Rosa, Miguel Á. De la

doi:10.1023/a:1006036105296

Cited by 12 publications

(4 citation statements)

References 31 publications

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“…Rapid Cytochrome c 6 Oxidation in Synechococcus. Our finding of rapid (t 1/2 ) 3 µs) electron transfer from cytochrome c 6 to PS I substantiates earlier reports of rapid (t 1/2 ) 10-40 µs) P700 + reduction in cyanobacteria in vivo (20)(21)(22) and in vitro (17,36) and suggests that fast electron transfer to PS I may be much more common in cyanobacteria than previously believed. The overall charge (P I value) of cyanobacterial cytochrome c 6 proteins is either basic or acidic.…”

Section: Discussionsupporting

confidence: 92%

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec₆inSynechococcussp. PCC 7002 in Vivo

et al. 2001

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Cytochrome c(6) donates electrons to photosystem I (PS I) in Synechococcus sp. PCC 7002. In this work, we provide evidence for rapid electron transfer (t(1/2) = 3 micros) from cytochrome c(6) to PS I in this cyanobacterium in vivo, indicating prefixation of the reduced donor protein to the photosystem. We have investigated the cytochrome c(6)-PS I interaction by laser flash-induced spectroscopy of intact and broken cells and by redox titrations of membrane and supernatant fractions. Redox studies revealed the expected membrane-bound cytochrome f, b(6), and b(559) species and two soluble cytochromes with alpha-band absorption peaks of 551 and 553 nm and midpoint potentials of -100 and 370 mV, respectively. The characteristics and the symmetrical alpha-band spectrum of the latter correspond to typical cyanobacterial cytochrome c(6) proteins. Rapid oxidation of cytochrome c(6) by PS I in vivo results in a unique, asymmetric oxidation spectrum, which differs significantly from the spectra obtained for cytochrome c(6) in solution. The basis for the unusual cytochrome c(6) spectrum and possible mechanisms of cytochrome c(6) fixation to PS I are discussed. The occurrence of rapid electron transfer to PS I in cyanobacteria suggests that this mechanism evolved before the endosymbiotic origin of chloroplasts. Its selective advantage may lie in protection against photo-oxidative damage as shown for Chlamydomonas.

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Section: Discussionsupporting

confidence: 92%

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec₆inSynechococcussp. PCC 7002 in Vivo

et al. 2001

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“…This then samples a number of orientations within the binding domain, with an optimal orientation for efficient ET being achieved by short-range forces such as hydrophobic contacts and possibly H-bonds ( , ). Previously, we and others have studied a number of redox protein complexes of either physiological or nonphysiological partners using both NMR ( − ) and kinetic ( − ) methodologies. These studies have yielded the solution structures of two such transient complexes ( , ) as well as information regarding the molecular recognition sites for others ( , ).…”

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confidence: 99%

Myoglobin and Cytochrome b₅: A Nuclear Magnetic Resonance Study of a Highly Dynamic Protein Complex

et al. 2002

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The transient complex of bovine myoglobin and cytochrome b(5) has been investigated using a combination of NMR chemical shift mapping, (15)N relaxation data, and protein docking simulations. Chemical shift perturbations observed for cytochrome b(5) amide resonances upon complex formation with either metmyoglobin (Fe(III)) or carbon monoxide-bound myoglobin (Fe(II)) are more than 10-fold smaller than in other transient redox protein complexes. From (15)N relaxation experiments, an increase in the overall correlation time of cytochrome b(5) in the presence of myoglobin is observed, confirming that complex formation is occurring. The chemical shift perturbations of proton and nitrogen amide nuclei as well as heme protons of cytochrome b(5) titrate with increasing myoglobin concentrations, also demonstrating the formation of a weak complex with a K(a) in the inverse millimolar range. The perturbed residues map over a wide surface area of cytochrome b(5), with patches of residues located around the exposed heme 6-propionate as well as at the back of the protein. The nature of the affected residues is mostly negatively charged contrary to perturbed residues in other transient complexes, which are mainly hydrophobic or polar. Protein docking simulations using the NMR data as constraints show several docking geometries both close to and far away from the exposed heme propionates of myoglobin. Overall, the data support the emerging view that this complex consists of a dynamic ensemble of orientations in which each protein constantly diffuses over the surface of the other. The characteristic NMR features may serve as a structural tool for the identification of such dynamic complexes.

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“…Whereas this model generally describes the recognition of Pc and cyt f, the exact nature of their complexes and critical molecular interactions remains under question and, furthermore, varies among species. 4,7,[12][13][14] The complexes can be stabilized by two regions of the proteins (Figure 1). A set of nonpolar residues surrounds the redox cofactors of both proteins creating "hydrophobic patches".…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous and Highly Dynamic Interface in Plastocyanin–Cytochrome f Complex Revealed by Site-Specific 2D-IR Spectroscopy

et al. 2019

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Transient protein complexes are crucial for sustaining dynamic cellular processes. The complexes of electron-transfer proteins are a notable example, such as those formed by plastocyanin (Pc) and cytochrome f (cyt f) in the photosynthetic apparatus. The dynamic and heterogeneous nature of these complexes, however, makes their study challenging. To better elucidate the complex of Nostoc Pc and cyt f, 2D-IR spectroscopy coupled to site-specific labeling with cyanophenylalanine infrared (IR) probes was employed to characterize how the local environments at sites along the surface of Pc were impacted by cyt f binding. The results indicate that Pc most substantially engages with cyt f via the hydrophobic patch around the copper redox site. Complexation with cyt f led to an increase in inhomogeneous broadening of the probe absorptions, reflective of increased heterogeneity of interactions with their environment. Notably, most of the underlying states interconverted very rapidly (1 to 2 ps), suggesting a complex with a highly mobile interface. The data support a model of the complex consisting of a large population of an encounter complex. Additionally, the study demonstrates the application of 2D-IR spectroscopy with site-specifically introduced probes to reveal new quantitative insight about dynamic biochemical systems.

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Cited by 12 publications

References 31 publications

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec₆inSynechococcussp. PCC 7002 in Vivo

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec₆inSynechococcussp. PCC 7002 in Vivo

Myoglobin and Cytochrome b₅: A Nuclear Magnetic Resonance Study of a Highly Dynamic Protein Complex

Heterogeneous and Highly Dynamic Interface in Plastocyanin–Cytochrome f Complex Revealed by Site-Specific 2D-IR Spectroscopy

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Untitled

Cited by 12 publications

References 31 publications

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec6inSynechococcussp. PCC 7002 in Vivo

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec6inSynechococcussp. PCC 7002 in Vivo

Myoglobin and Cytochrome b5: A Nuclear Magnetic Resonance Study of a Highly Dynamic Protein Complex

Heterogeneous and Highly Dynamic Interface in Plastocyanin–Cytochrome f Complex Revealed by Site-Specific 2D-IR Spectroscopy

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Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec₆inSynechococcussp. PCC 7002 in Vivo

Rapid Electron Transfer to Photosystem I and Unusual Spectral Features of Cytochromec₆inSynechococcussp. PCC 7002 in Vivo

Myoglobin and Cytochrome b₅: A Nuclear Magnetic Resonance Study of a Highly Dynamic Protein Complex