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1
المؤلفون: Susan J. Firbank, Christopher Dennison, Mark J. Banfield, Pedro M. Matias, Hualing Mi, Peter B. Crowley
المصدر: Biochemistry. 47:6583-6589
مصطلحات موضوعية: Models, Molecular, Protein Conformation, Chemistry, Supramolecular chemistry, Crystallography, X-Ray, Cyanobacteria, Biochemistry, Acceptor, Electron transport chain, Protein Structure, Secondary, Recombinant Proteins, Electron Transport, Crystal, Crystallography, Electron transfer, Bacterial Proteins, Side chain, Molecule, Protein Multimerization, Crystallization, Plastocyanin, Copper, Protein Binding
الوصف: The accepted view of interprotein electron transport involves molecules diffusing between donor and acceptor redox sites. An emerging alternative hypothesis is that efficient long-range electron transport can be achieved through proteins arranged in supramolecular assemblies. In this study, we have investigated the crystal packing interfaces in three crystal forms of plastocyanin, an integral component of the photosynthetic electron transport chain, and discuss their potential relevance to in vivo supramolecular assemblies. Symmetry-related protein chains within these crystals have Cu-Cu separations of
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7648a85e9f1dafaac5e2cb3f7a758cdeTest
https://doi.org/10.1021/bi800125hTest -
2
المؤلفون: William McFarlane, Mark J. Banfield, Sachiko Yanagisawa, David Hunter, Peter B. Crowley, Anne T. Lawler, Chan Li, Christopher Dennison, Susan J. Firbank, Takamitsu Kohzuma
المصدر: Journal of the American Chemical Society. 130(46)
مصطلحات موضوعية: Models, Molecular, Dryopteris, Coordination sphere, Stereochemistry, Protonation, Electrons, Crystallography, X-Ray, Cyanobacteria, Ligands, Biochemistry, Redox, Achromobacter cycloclastes, Catalysis, Electron transfer, Colloid and Surface Chemistry, Catalytic Domain, Metalloproteins, Plastocyanin, Nuclear Magnetic Resonance, Biomolecular, biology, Chemistry, Wild type, Active site, General Chemistry, Hydrogen-Ion Concentration, Electron transport chain, Protein Structure, Tertiary, biology.protein, Oxidation-Reduction, Copper, Protein Binding
الوصف: The influence of π-interactions with a His ligand have been investigated in a family of copper-containing redox metalloproteins. The Met16Phe and Met16Trp pseudoazurin, and Leu12Phe spinach and Leu14Phe Phormidium laminosum plastocyanin variants possess active-site π-contacts between the introduced residue and His81 and His87/92 respectively. The striking overlap of the side chain of Phe16 in the Met1 6Phe variant and that of Met16 in wild type pseudoazurin identifies that this position provides an important second coordination sphere interaction in both cases. His-ligand protonation and dissociation from Cu(I) occurs in the wild type proteins resulting in diminished redox activity, providing a [H + ]-driven switch for regulating electron transfer. The introduced π-interaction has opposing effects on the pK a for the His ligand in pseudoazurin and plastocyanin due to subtle differences in the π-contact, stabilizing the coordinated form of pseudoazurin whereas in plastocyanin protonation and dissociation is favored. Replacement of Pro36, a residue that has been suggested to facilitate structural changes upon His ligand protonation, with a Gly, has little effect on the pK a of His87 in spinach plastocyanin. The mutations at Met16 have a significant influence on the reduction potential of pseudoazurin. Electron self-exchange is enhanced, whereas association with the physiological partner, nitrite reductase, is only affected by the Met16Phe mutation, but k cat is halved in both the Met16Phe and Met16Trp variants. Protonation of the His ligand is the feature most affected by the introduction of a π-interaction.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d45af11f251a368b1a573fd3759bc17eTest
https://pubmed.ncbi.nlm.nih.gov/18939838Test -
3
المؤلفون: Christopher Dennison, Katsuko Sato, Peter B. Crowley
المصدر: The Journal of biological chemistry. 280(19)
مصطلحات موضوعية: Models, Molecular, Magnetic Resonance Spectroscopy, Protein Conformation, Molecular Sequence Data, Electrons, Sodium Chloride, Crystallography, X-Ray, Cyanobacteria, Biochemistry, Redox, Ion, Reaction rate constant, Azurin, Chlorophyta, Spinacia oleracea, Escherichia coli, Magnesium, Amino Acid Sequence, Plastocyanin, Molecular Biology, Ions, biology, Sequence Homology, Amino Acid, Chemistry, Temperature, Cell Biology, Hydrogen-Ion Concentration, biology.organism_classification, Crystallography, Kinetics, Ionic strength, Thylakoid, Spinach, Dimerization, Oxidation-Reduction, Anabaena variabilis, Protein Binding
الوصف: Transient homodimer protein interactions have been investigated by analyzing the influence of ionic strength (NaCl) on the electron self-exchange (the bimolecular reaction whereby the two oxidation states of a redox protein interconvert) rate constant (kese) of four plastocyanins. The kese values for the plastocyanins from spinach, Dryopteris crassirhizoma (a fern), and the green alga Ulva pertusa, which possess acidic patches of varying size and locations, increase 190-, 29-, and 21-fold, respectively, at elevated ionic strength (I = 2.03 m). In contrast, the kese for the almost neutral cyanobacterial plastocyanin from Anabaena variabilis exhibits very little dependence on ionic strength. The temperature dependence of the kese for spinach plastocyanin (I = 0.28 m) provides evidence for poor packing at the homodimer interface. Representative structures of the transient homodimers involved in electron self-exchange, which are consistent with fits of the ionic strength dependence of kese to van Leeuwen theory, have been obtained from protein modeling and docking simulations. The Coulombic energy of the docked homodimers follows the order spinach > D. crassirhizoma > U. pertusa > A. variabilis, which matches that of the overall influence of ionic strength on kese. Analysis of the homodimer structures indicates that poor packing and high planarity are features of the interface that favor transient interactions. The physiologically relevant Mg2+ ion has a much more pronounced influence on the kese of spinach plastocyanin, which along with the known properties of the thylakoid lumen suggests a biological role for electron self-exchange.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::627d2fd9484135e7aab2a5a48de4cc68Test
https://pubmed.ncbi.nlm.nih.gov/15743773Test -
4
المؤلفون: Miguel A. De la Rosa, Irene Díaz-Moreno, Peter B. Crowley, Marcellus Ubbink, Antonio Díaz-Quintana
المصدر: Digital.CSIC. Repositorio Institucional del CSIC
instnameمصطلحات موضوعية: Models, Molecular, Nostoc, Cytochrome, Static Electricity, Cytochrome f, Cyanobacteria, Photosynthesis, Photochemistry, Biochemistry, Electron transfer, Plastocyanin, Nuclear Magnetic Resonance, Biomolecular, biology, Cytochrome b6f complex, Osmolar Concentration, Nuclear magnetic resonance spectroscopy, biology.organism_classification, Binding constant, Cytochromes f, Multiprotein Complexes, biology.protein, Biophysics, Hydrophobic and Hydrophilic Interactions, Cyanobacterium, Protein Binding
الوصف: 8 páginas, 6 figuras, 1 tabla
The highly efficient electron-transfer chain in photosynthesis demonstrates a remarkable variation among organisms in the type of interactions between the soluble electron-transfer protein plastocyanin and it partner cytochrome f. The complex from the cyanobacterium Nostoc sp. PCC 7119 was studied using nuclear magnetic resonance spectroscopy and compared to that of the cyanobacterium Phormidium laminosum. In both systems, the main site of interaction on plastocyanin is the hydrophobic patch. However, the interaction in the Nostoc complex is highly dependent on electrostatics, contrary to that of Phormidium, resulting in a binding constant that is an order of magnitude larger at low ionic strength for the Nostoc complex. Studies of the mixed complexes show that these differences in interactions are mainly attributable to the surface properties of the plastocyanins.
This work was supported by grants from the Improving Human Potential Program of the European Commission (contract no. HPRNCT- 1999-00095), by the Spanish Ministry of Science and Technology (Grant BMC2003-00458), and by The Netherlands Organisation for Scientific Research (Grant 700.52.425). I.D.-M. was also the recipient of an individual fellowship from the Spanish Ministry of Education, Culture, and Sport(AP2000-2937).الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::49d14e54225fccf1f276d9384a219f1eTest
http://hdl.handle.net/10261/33655Test -
5
المصدر: Biochemistry. 41(52)
مصطلحات موضوعية: Proline, Macromolecular Substances, Glycine, Prochlorothrix, Cyanobacteria, Biochemistry, Leucine, Histidine, Spectroscopy, Plastocyanin, Nuclear Magnetic Resonance, Biomolecular, Conserved Sequence, Cytochrome f, Binding Sites, Chemistry, Nuclear magnetic resonance spectroscopy, Binding constant, Cytochromes f, Crystallography, Ionic strength, Mutagenesis, Site-Directed, Cytochromes, Tyrosine, Titration, Protons, Hydrophobic and Hydrophilic Interactions, Stoichiometry
الوصف: Transient complex formation between plastocyanin from Prochlorothrix hollandica and cytochrome f from Phormidium laminosum was investigated using nuclear magnetic resonance (NMR) spectroscopy. Binding curves derived from NMR titrations at 10 mM ionic strength reveal a 1:1 stoichiometry and a binding constant of 6 (+/-2) x 10(3) M(-1) for complex formation, 1 order of magnitude larger than that for the physiological plastocyanin-cytochrome f complex from Ph. laminosum. Chemical-shift perturbation mapping indicates that the hydrophobic patch of plastocyanin is involved in the complex interface. When the unusual hydrophobic patch residues of P. hollandica plastocyanin were reverted to the conserved residues found in most other plastocyanins (Y12G/P14L), the binding constant for the interaction with cytochrome f was unaffected. However, the chemical shift perturbation map was considerably different, and the size of the average perturbation decreased by 40%. The complexes of both the wild-type and double mutant plastocyanin with cytochrome f were sensitive to ionic strength, contrary to the physiological complex. The possible implications of these findings for the mechanism of transient complex formation are discussed.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2a22411c0be31b2e3e676805fad515baTest
https://pubmed.ncbi.nlm.nih.gov/12501198Test -
6
المؤلفون: Miguel A. De la Rosa, Marcellus Ubbink, Martin Sutter, Peter B. Crowley, Wolfgang Haehnel, Pedro M. Nieto, Antonio Díaz-Quintana, Fernando P. Molina-Heredia
المساهمون: Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular, European Commission (EC), Ministerio de Ciencia Y Tecnología (MCYT). España, Junta de Andalucía
المصدر: Journal of Biological Chemistry, 277(50), 48685-48689
idUS. Depósito de Investigación de la Universidad de Sevilla
instnameمصطلحات موضوعية: Cytochrome f, Models, Molecular, biology, Cytochrome, Cytochrome b, Cytochrome b6f complex, Stereochemistry, Protein Conformation, Cytochrome c, Cell Biology, Photochemistry, Cyanobacteria, Biochemistry, Cytochromes f, Cytochrome C1, Coenzyme Q – cytochrome c reductase, biology.protein, Cytochrome c oxidase, Cytochromes, Molecular Biology, Nuclear Magnetic Resonance, Biomolecular, Protein Binding
الوصف: During oxygenic photosynthesis, cytochromec6 shuttles electrons between the membrane-bound complexes cytochrome bf and photosystem I. Complex formation between Phormidium laminosum cytochromef and cytochrome c6 from bothAnabaena sp. PCC 7119 and Synechococcus elongatus has been investigated by nuclear magnetic resonance spectroscopy. Chemical-shift perturbation analysis reveals a binding site on Anabaena cytochrome c6, which consists of a predominantly hydrophobic patch surrounding the heme substituent, methyl 5. This region of the protein was implicated previously in the formation of the reactive complex with photosytem I. In contrast to the results obtained for Anabaena cytochromec6, there is no evidence for specific complex formation with the acidic cytochrome c6 fromSynechococcus. This remarkable variability between analogous cytochromes c6 supports the idea that different organisms utilize distinct mechanisms of photosynthetic intermolecular electron transfer. European Commission HPRN-CT-1999-00095 Spanish Ministry of Science and Technology BMC2000-0444 Andalusian Government CVI-0198
وصف الملف: application/pdf
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::641ab0f1f9ee533ed3b4317964377e8cTest
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7
المؤلفون: Gerard W. Canters, Peter B. Crowley, Gottfried Otting, Marcellus Ubbink, Beatrix G. Schlarb-Ridley
المصدر: Journal of the American Chemical Society. 123(43)
مصطلحات موضوعية: Cytochrome, Stereochemistry, Protein Conformation, Surface Properties, Photosynthetic Reaction Center Complex Proteins, Cyanobacteria, Biochemistry, Catalysis, Hydrophobic effect, chemistry.chemical_compound, Colloid and Surface Chemistry, Bacterial Proteins, Molecule, Plastocyanin, Heme, Nuclear Magnetic Resonance, Biomolecular, Cytochrome f, biology, Nitrogen Isotopes, Chemistry, Cytochrome b6f complex, Osmolar Concentration, General Chemistry, Hydrogen-Ion Concentration, Cytochromes f, Ionic strength, biology.protein, Cytochromes
الوصف: The complex of the photosynthetic redox partners plastocyanin and cytochrome f from the thermophilic cyanobacterium, Phormidium laminosum, was investigated by nuclear magnetic resonance (NMR). Chemical-shift perturbation analysis of amide proton and nitrogen nuclei implicates the hydrophobic patch and, to a lesser extent, the "eastern face" of plastocyanin in the complex interface. Intermolecular pseudocontact shifts observed in the complex of cadmium-substituted plastocyanin and ferric cytochrome f specifically define the site of interaction to be between the hydrophobic patch of plastocyanin and the heme region of cytochrome f. Rigid-body structure calculations using NMR-derived restraints demonstrate that plastocyanin is oriented in a "head-on" fashion, with the long axis of the molecule perpendicular to the heme plane. Remarkably, the structure and affinity of the complex are independent of ionic strength, indicating that there is little electrostatic interaction. Lowering the pH results in limited reorganization of the complex interface, while the binding affinity is unaffected. Therefore, protonation of the exposed copper ligand, His92, plays only a minor role in the complex. In contrast to other electron-transfer complexes, the plastocyanin-cytochrome f complex from P. laminosum is predominantly controlled by hydrophobic interactions. These findings are discussed in the context of the previously characterized angiosperm complex.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::98193713c70e382a353fa9ea47c9d80eTest
https://pubmed.ncbi.nlm.nih.gov/11673974Test
