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David B Knaff - One of the best experts on this subject based on the ideXlab platform.

  • the role of high potential iron protein and cytochrome c8 as alternative electron donors to the reaction center of Chromatium vinosum
    Biochemistry, 2002
    Co-Authors: Andre Vermeglio, Barbara Schoeppcothenet, Neil Pratt, David B Knaff
    Abstract:

    Under anaerobic conditions, intact cells of the purple sulfur bacterium Chromatium vinosum exhibit rapid photooxidation of the two low-potential hemes of the c-type cytochrome associated with the r...

  • Genes encoding light-harvesting and reaction center proteins from Chromatium vinosum
    Photosynthesis Research, 1999
    Co-Authors: Gary E. Corson, Kenji V. P. Nagashima, Katsumi Matsuura, Yumiko Sakuragi, Ruwanthi Wettasinghe, Hong Qin, Randy Allen, David B Knaff
    Abstract:

    Sequencing of a 3.4 kb DNA fragment isolated from the photosynthetic purple sulfur bacterium Chromatium vinosum and of PCR products has resulted in identification of the Chr. vinosum pufL, pufM, and pufC genes, reading from the 5′ to the 3′ direction, and coding, respectively, for the L, M and cytochrome c subunits of the reaction center of this bacterium. Other PCR products have been used to obtain complete sequences for the pufB and pufA genes, located immediately upstream from pufL and encoding the apoproteins of two Chr. vinosum light- harvesting proteins. The 3′-portion of the bchZ gene, a gene that codes for a protein involved in the biosynthesis of bacteriochlorophyll, has been located immediately upstream from pufB. A second pufB gene, pufB2, has been located downstream from pufC, as has the 5′-portion of a second pufA gene, pufA2. The location of a second set of pufB and pufA genes, encoding light- harvesting proteins, downstream from pufC has not previously been reported for any photosynthetic bacterium. Translation of the gene sequences encoding these Chr. vinosum light-harvesting proteins reveals both similarities to and differences from the amino acid sequences, obtained from direct sequencing of the apoproteins, previously reported for Chr. vinosum light-harvesting proteins. Translation of these gene sequences, and of those for pufL, pufM and pufC, revealed significant homology, at the amino acid level, to the corresponding peptides of photosynthetic purple non-sulfur bacteria.

  • Isolation and characterization of soluble electron transfer proteins from Chromatium purpuratum
    Biochemistry, 1996
    Co-Authors: Cheryl A. Kerfeld, Cheryl Chan, Masakazu Hirasawa, Susan Kleis-sanfrancisco, Todd O. Yeates, David B Knaff
    Abstract:

    Several soluble electron transfer proteins were isolated and characterized from the marine purple-sulfur bacterium Chromatium purpuratum. The C. purpuratum flavocytochrome c is similar in molecular mass (68 kDa) and isoelectric point (6.5) to flavocytochromes isolated from other phototrophs. Redox titrations of the flavocytochrome c hemes show two components with midpoint potential values of +15 and −120 mV, behavior similar to that observed with the flavocytochrome isolated from the thermophilic Chromatium tepidum. Moreover, N-terminal amino acid sequence analysis of both the flavin and the cytochrome subunit indicates substantial homology to the primary structure of the flavocytochrome c of Chromatium vinosum. In contrast, the C. purpuratum high-potential iron−sulfur protein (HiPIP) differs from those isolated from other photosynthetic bacteria in its relatively high midpoint potential (+390 mV) and the possibility that it exists as a dimer in solution. Two low molecular mass c-type cytochromes were als...

J A Cowan - One of the best experts on this subject based on the ideXlab platform.

  • factors influencing redox thermodynamics and electron self exchange for the fe4s4 cluster in Chromatium vinosum high potential iron protein the role of core aromatic residues in defining cluster redox chemistry
    Biochemistry, 1996
    Co-Authors: Aileen Soriano, Shumin Bian, And Anshu Agarwal, J A Cowan
    Abstract:

    The roles of aromatic core residues in regulating the reduction potential, the enthalpy and entropy of reduction, and the self-exchange rate constants for electron-transfer reactions for the prosthetic [Fe4S4]3+/2+ cluster of Chromatium vinosum high potential iron protein (HiPIP) have been addressed by a combination of site-directed mutagenesis, high field NMR (EXSY) experiments, and variable temperature spectrochemical redox titration measurements. Minimal changes are observed following nonconservative mutation of residues Tyr19, Phe48, and Phe66. Apparently these hydrophobic residues play only a minor role in defining the electronic properties of the cluster. These data support a model, first defined from results obtained on Tyr19 mutant HiPIP's [Agarwal, A., Li, D., & Cowan, J. A. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 9440−9444], in which the aromatic core restricts solvent accessibility and thereby stabilizes the oxidized [Fe4S4]3+ cluster.

  • role of aromatic residues in stabilization of the fe4s4 cluster in high potential iron proteins hipips physical characterization and stability studies of tyr 19 mutants of Chromatium vinosum hipip
    Proceedings of the National Academy of Sciences of the United States of America, 1995
    Co-Authors: Anshu Agarwal, J A Cowan
    Abstract:

    Abstract The functional role of residue Tyr-19 of Chromatium vinosum HiPIP has been evaluated by site-directed mutagenesis experiments. The stability of the [Fe4S4] cluster prosthetic center is sensitive to side-chain replacements. Polar residues result in significant instability, while nonpolar residues (especially with aromatic side chains) maintain cluster stability. Two-dimensional NMR data of native and mutant HiPIPs are consistent with a model where Tyr-19 serves to preserve the structural rigidity of the polypeptide backbone, thereby maintaining a hydrophobic barrier for exclusion of water from the cluster cavity. Solvent accessibility results in more facile oxidation of the cluster by atmospheric oxygen, with subsequent rapid hydrolysis of the [Fe4S4]3+ core.

  • synthesis cloning and expression of a synthetic gene for high potential iron protein from Chromatium vinosum
    Biochemical and Biophysical Research Communications, 1993
    Co-Authors: Anshu Agarwal, Jian Tan, Mesut Eren, A Tevelev, Siu Man Lui, J A Cowan
    Abstract:

    Abstract A synthetic gene encoding the peptide sequence for the low molecular weight (Mr ∼ 9600 Da) high-potential iron protein (HiPIP) from the photosynthetic bacterium Chromatium vinosum has been constructed by shotgun ligation of twelve complimentary oligonudeotides varying in size from 42-mers to 48-mers. After cloning the gene into a pET-21d(+) vector, expression of holoprotein in yields of 35 mg/liter of culture was obtained following induction with isopropyl-β-D-thiogalactoside (IPTG). The recombinant protein was characterized by electronic absorption, 1H NMR, electrochemistry, N-terminal sequencing and amino acid analysis. This is the first example of the expression of a high potential ferredoxin containing a fully constituted [Fe4S4] cluster.

Ivano Bertini - One of the best experts on this subject based on the ideXlab platform.

  • the three dimensional solution structure of the reduced high potential iron sulfur protein from Chromatium vinosum through nmr
    Biochemistry, 1995
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Alexander Dikiy, Dieter H W Kastrau, Pornthep Sompornpisut
    Abstract:

    The 1H NMR assignment of the reduced HiPIP from Chromatium vinosum available in the literature [Gaillard, J., Albrand, J.-P., Moulis, J.-M., & Wemmer, D. E. (1992) Biochemistry 31, 5632-5639] has been extended up to 85% of the total protein protons. Ninety percent of the nitrogens have been assigned. Then the solution structure has been obtained using as many as 1147 meaningful NOE connectivities. The protein is sizably paramagnetic even though the ground state is a singlet. Nevertheless, the final RMSD values are 0.62 and 1.19 A for the backbone and the heavy atoms, respectively. These values compare well with those for diamagnetic proteins of the same size. The solution structure is discussed in the light of the available structural information from X-ray data.

  • the iron sulfur cluster in the oxidized high potential iron protein from ectothiorhodospira halophila
    Journal of the American Chemical Society, 1993
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Francesco Capozzi, Paolo Carloni, Stefano Ciurli, Mario Piccioli
    Abstract:

    In our efforts to characterize oxidized high-potential iron-sulfur proteins (HiPIP), we have investigated the oxidized HiPIP II from Ectothiorhodospira halophila through 1 H NMR and molecular dynamics (MD) calculations. This protein has the most symmetric isotropic shift pattern of the β-CH 2 protons of the liganded cysteines, four signals being upfield and four downfield. 1 H NOE, NOESY, and TOCSY results have provided the necessary key connectivities to perform the assignment of the liganded cysteines, taking advantage of the structure of the HiPIP I isoprotein. It is found that the electronic distribution within the cluster is different with respect to the Chromatium vinosum and Rhodocyclus gelatinosus systems

  • molecular dynamics simulations on hipip from Chromatium vinosum and comparison with nmr data
    Journal of the American Chemical Society, 1992
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Paolo Carloni, Pier Luigi Orioli
    Abstract:

    The solution structure of HiPIP from Chromatium vinosum has been modeled through molecular dynamics (MD) calculations and compared with the X-ray structure. This is the first attempt to investigate open shell ions in a polymetallic system through MD. The results have been compared with available NOE constraints, which are definitely in better agreement with the MD model than with the X-ray structure. This contribution opens the route to the investigation of iron-sulfur proteins through the combined use of MD and NMR

  • identification of the iron ions of high potential iron protein from Chromatium vinosum within the protein frame through two dimensional nmr experiments
    Journal of the American Chemical Society, 1992
    Co-Authors: Ivano Bertini, Claudio Luchinat, Francesco Capozzi, Stefano Ciurli, Luigi Messori, Mario Piccioli
    Abstract:

    2D NMR experiments performed on both the oxidized and reduced form of the high potential iron protein (HiPIP) from Chromatium vinosum, a paramagnetic iron sulfur protein for which the crystal structure is known in both oxidation states, allowed us to detect a number of scalar and dipolar connectivities of the isotropically shifted signals. On this basis it was possible to firmly identify the signals of the β-CH 2 and α-CH protons of the cluster-liganded cysteines and perform their sequence-specific assignments

  • noe and two dimensional correlated 1h nmr spectroscopy of cytochrome c from Chromatium vinosum
    FEBS Journal, 1992
    Co-Authors: Lucia Banci, Ivano Bertini, Paola Turano, Margarita Vicens Oliver
    Abstract:

    1H two-dimensional (nuclear Overhauser effect spectroscopy (NOESY) and two-dimensional correlated spectroscopy (COSY) spectra of cytochrome c' from Chromatium vinosum have been obtained. The protein is of medium size (Mr 28,000), essentially high spin (S = 5/2) although some quantum mechanical spin admixing with S = 3 2 may be present. Under these circumstances NOESY cross peaks have been revealed between geminal protons (alpha-CH2 propionate and beta-CH2 protons of the bound histidine) and between alpha-CH2 propionate protons and the heme methyl groups. COSY maps have confirmed the geminal nature of the proton pairs, even with a linewidth as large as 900 Hz; the J value is about 12 Hz. This assignment has rationalized on a sound basis the biochemical behavior of this protein with pH and has showed the utility of this kind of spectroscopy for the other cytochromes c' structures and analogous systems.

Lucia Banci - One of the best experts on this subject based on the ideXlab platform.

  • the three dimensional solution structure of the reduced high potential iron sulfur protein from Chromatium vinosum through nmr
    Biochemistry, 1995
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Alexander Dikiy, Dieter H W Kastrau, Pornthep Sompornpisut
    Abstract:

    The 1H NMR assignment of the reduced HiPIP from Chromatium vinosum available in the literature [Gaillard, J., Albrand, J.-P., Moulis, J.-M., & Wemmer, D. E. (1992) Biochemistry 31, 5632-5639] has been extended up to 85% of the total protein protons. Ninety percent of the nitrogens have been assigned. Then the solution structure has been obtained using as many as 1147 meaningful NOE connectivities. The protein is sizably paramagnetic even though the ground state is a singlet. Nevertheless, the final RMSD values are 0.62 and 1.19 A for the backbone and the heavy atoms, respectively. These values compare well with those for diamagnetic proteins of the same size. The solution structure is discussed in the light of the available structural information from X-ray data.

  • the iron sulfur cluster in the oxidized high potential iron protein from ectothiorhodospira halophila
    Journal of the American Chemical Society, 1993
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Francesco Capozzi, Paolo Carloni, Stefano Ciurli, Mario Piccioli
    Abstract:

    In our efforts to characterize oxidized high-potential iron-sulfur proteins (HiPIP), we have investigated the oxidized HiPIP II from Ectothiorhodospira halophila through 1 H NMR and molecular dynamics (MD) calculations. This protein has the most symmetric isotropic shift pattern of the β-CH 2 protons of the liganded cysteines, four signals being upfield and four downfield. 1 H NOE, NOESY, and TOCSY results have provided the necessary key connectivities to perform the assignment of the liganded cysteines, taking advantage of the structure of the HiPIP I isoprotein. It is found that the electronic distribution within the cluster is different with respect to the Chromatium vinosum and Rhodocyclus gelatinosus systems

  • molecular dynamics simulations on hipip from Chromatium vinosum and comparison with nmr data
    Journal of the American Chemical Society, 1992
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Paolo Carloni, Pier Luigi Orioli
    Abstract:

    The solution structure of HiPIP from Chromatium vinosum has been modeled through molecular dynamics (MD) calculations and compared with the X-ray structure. This is the first attempt to investigate open shell ions in a polymetallic system through MD. The results have been compared with available NOE constraints, which are definitely in better agreement with the MD model than with the X-ray structure. This contribution opens the route to the investigation of iron-sulfur proteins through the combined use of MD and NMR

  • noe and two dimensional correlated 1h nmr spectroscopy of cytochrome c from Chromatium vinosum
    FEBS Journal, 1992
    Co-Authors: Lucia Banci, Ivano Bertini, Paola Turano, Margarita Vicens Oliver
    Abstract:

    1H two-dimensional (nuclear Overhauser effect spectroscopy (NOESY) and two-dimensional correlated spectroscopy (COSY) spectra of cytochrome c' from Chromatium vinosum have been obtained. The protein is of medium size (Mr 28,000), essentially high spin (S = 5/2) although some quantum mechanical spin admixing with S = 3 2 may be present. Under these circumstances NOESY cross peaks have been revealed between geminal protons (alpha-CH2 propionate and beta-CH2 protons of the bound histidine) and between alpha-CH2 propionate protons and the heme methyl groups. COSY maps have confirmed the geminal nature of the proton pairs, even with a linewidth as large as 900 Hz; the J value is about 12 Hz. This assignment has rationalized on a sound basis the biochemical behavior of this protein with pH and has showed the utility of this kind of spectroscopy for the other cytochromes c' structures and analogous systems.

Claudio Luchinat - One of the best experts on this subject based on the ideXlab platform.

  • the three dimensional solution structure of the reduced high potential iron sulfur protein from Chromatium vinosum through nmr
    Biochemistry, 1995
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Alexander Dikiy, Dieter H W Kastrau, Pornthep Sompornpisut
    Abstract:

    The 1H NMR assignment of the reduced HiPIP from Chromatium vinosum available in the literature [Gaillard, J., Albrand, J.-P., Moulis, J.-M., & Wemmer, D. E. (1992) Biochemistry 31, 5632-5639] has been extended up to 85% of the total protein protons. Ninety percent of the nitrogens have been assigned. Then the solution structure has been obtained using as many as 1147 meaningful NOE connectivities. The protein is sizably paramagnetic even though the ground state is a singlet. Nevertheless, the final RMSD values are 0.62 and 1.19 A for the backbone and the heavy atoms, respectively. These values compare well with those for diamagnetic proteins of the same size. The solution structure is discussed in the light of the available structural information from X-ray data.

  • the iron sulfur cluster in the oxidized high potential iron protein from ectothiorhodospira halophila
    Journal of the American Chemical Society, 1993
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Francesco Capozzi, Paolo Carloni, Stefano Ciurli, Mario Piccioli
    Abstract:

    In our efforts to characterize oxidized high-potential iron-sulfur proteins (HiPIP), we have investigated the oxidized HiPIP II from Ectothiorhodospira halophila through 1 H NMR and molecular dynamics (MD) calculations. This protein has the most symmetric isotropic shift pattern of the β-CH 2 protons of the liganded cysteines, four signals being upfield and four downfield. 1 H NOE, NOESY, and TOCSY results have provided the necessary key connectivities to perform the assignment of the liganded cysteines, taking advantage of the structure of the HiPIP I isoprotein. It is found that the electronic distribution within the cluster is different with respect to the Chromatium vinosum and Rhodocyclus gelatinosus systems

  • molecular dynamics simulations on hipip from Chromatium vinosum and comparison with nmr data
    Journal of the American Chemical Society, 1992
    Co-Authors: Lucia Banci, Ivano Bertini, Claudio Luchinat, Paolo Carloni, Pier Luigi Orioli
    Abstract:

    The solution structure of HiPIP from Chromatium vinosum has been modeled through molecular dynamics (MD) calculations and compared with the X-ray structure. This is the first attempt to investigate open shell ions in a polymetallic system through MD. The results have been compared with available NOE constraints, which are definitely in better agreement with the MD model than with the X-ray structure. This contribution opens the route to the investigation of iron-sulfur proteins through the combined use of MD and NMR

  • identification of the iron ions of high potential iron protein from Chromatium vinosum within the protein frame through two dimensional nmr experiments
    Journal of the American Chemical Society, 1992
    Co-Authors: Ivano Bertini, Claudio Luchinat, Francesco Capozzi, Stefano Ciurli, Luigi Messori, Mario Piccioli
    Abstract:

    2D NMR experiments performed on both the oxidized and reduced form of the high potential iron protein (HiPIP) from Chromatium vinosum, a paramagnetic iron sulfur protein for which the crystal structure is known in both oxidation states, allowed us to detect a number of scalar and dipolar connectivities of the isotropically shifted signals. On this basis it was possible to firmly identify the signals of the β-CH 2 and α-CH protons of the cluster-liganded cysteines and perform their sequence-specific assignments