羟氨苄青霉素引起大疱性类天疱疮样疹

Characteristics and Activities of Sulfate-reducing Bacteria L.L. Barton, F.A. Tomei. Sulfate-reducing Archaea R.K. Thauer, J. Kunow. Taxonomic Relationships E. Stackebrandt, et al. Respiratory Sulfate Reduction J.M. Akagi. Characteristics of Electron Transfer Proteins L. Chen, et al. Solute Transport and Cell Energetics H. Cypionka. Molecular Biology of Redoxactive Metal Proteins from Desulfovibrio W.M.A.M. van Dongen. Ecology of Sulfate-reducing Bacteria G.D. Fauque. Biocorrosion W.A. Hamilton, W. Lee. Control in Industrial Settings T.R. Jack, D.W.S. Westlake. Metabolism of Environmental Contaminants by Mixed and Pure Cultures of Sulfate-reducing Bacteria B.D. Ensley, J.M. Suflita. Index.

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Sulfate-reducing bacteria

NMR studies of water bound to biological molecules

Isotope labeling in solution protein assignment and structural analysis

Recently proposed self-consistent 3J coupling analysis (Schmidt, J. M.; Blumel, M.; Lohr, F.; Ruterjans, H. J. Biomol. NMR 1999, 14, 1-12) has been carried out to calibrate Karplus parameters constituting the empirical dependence of 3J coupling constants on the chi1 dihedral angle in amino acid side chains. The procedure involves simultaneous least-squares optimization of six sets of three Karplus coefficients related to all six 3J coupling types accessible in 15N,13C-labeled proteins. A simple concept of fundamental and incremental component couplings is proposed to account for substituent effects, eventually yielding amino acid topology-specific Karplus parameters. The method is exemplified with recombinant Desulfovibrio vulgaris flavodoxin (147 amino acids, 16 kDa) with reference to a total of 749 experimental 3JHalpha,Hbeta, 3JN',Hbeta, 3JC',Hbeta, 3JHalpha,Cgamma, 3JN',Cgamma, and 3JC',Cgamma coupling constants. Unlike other parametrizations, the present method does not make reference to X-ray coordinates, so that the Karplus coefficients obtained are not influenced by differences between solution and crystal states. Cross validation using X-ray torsion angles demonstrates the improvement relative to previous parametrizations. The Karplus coefficients derived are applicable to other proteins, too. Parameter refinement also yields a series of chi1 torsion angles, providing valuable constraints for protein structure determination, as well as optional parameters of local angular mobility in the contexts of Gaussian random fluctuation or a three-site jump model. The procedure permits automatic stereospecific assignments of Hbeta and Cgamma chemical shifts. The majority of the flavodoxin side-chain conformations agrees with high-resolution X-ray structures of the protein. Marked deviations between NMR and X-ray datasets are attributed to different rotameric states due to crystal-packing effects and to conformational equilibria between multiple chi1 rotamers.

Self-consistent Karplus parametrization of 3J couplings depending on the polypeptide side-chain torsion chi1.

Flavodoxin from Desulfovibrio vulgaris (Hildenborough) has been expressed at a high level (3-4% soluble protein) in Escherichia coli by subcloning a minimal insert carrying the gene behind the tac promoter of plasmid pDK6. The recombinant protein was readily isolated and its properties were shown to be identical to those of the wild-type protein obtained directly from D. vulgaris, with the exception that the recombinant protein lacks the N-terminal methionine residue. Detailed measurements of the redox potentials of this flavodoxin are reported for the first time. The redox potential, E2, for the couple oxidized flavodoxin/flavodoxin semiquinone at pH 7.0 is -143 mV (25 degrees C), while the value for the flavodoxin semiquinone/flavodoxin hydroquinone couple (E1) at the same pH is -440 mV. The effects of pH on the observed potentials were examined; E2 varies linearly with pH (slope = -59 mV), while E1 is independent of pH at high pH values, but below pH 7.5 the potential becomes less negative with decreasing pH, indicating a redox-linked protonation of the flavodoxin hydroquinone. D. vulgaris apoflavodoxin binds FMN very tightly, with a value of 0.24 nM for the dissociation constant (Kd) at pH 7.0 and 25 degrees C, similar to that observed with other flavodoxins. In addition, the apoflavodoxin readily binds riboflavin (Kd = 0.72 microM; 50 mM sodium phosphate, pH 7.0, 5 mM EDTA at 25 degrees C) and the complex is spectroscopically very similar to that formed with FMN. The redox potentials for the riboflavin complex were determined at pH 6.5 (E1 = -262 mV, E2 = -193 mV; 25 degrees C) and are discussed in the light of earlier proposals that charge/charge interactions between different parts of the flavin hydroquinone play a crucial role in determining E1 in flavodoxin.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1991.tb16475.x

Redox and flavin‐binding properties of recombinant flavodoxin from Desulfovibrio vulgaris (Hildenborough)

Recombinant Desulfovibrio vulgaris flavodoxin (molecular mass 16.3 kDa) was produced in Escherichia coli. The oxidized protein has been investigated with a combination of homonuclear and heteronuclear two-dimensional and heteronuclear three-dimensional NMR spectroscopy. Sequencespecific assignment of all backbone and most of the side chain 1H and 15N resonances has been obtained. The secondary structure has been inferred from the pattern of sequential, medium-, and long-range NOEs, together with information about slowly exchanging amide hydrogens and HN-Hα spin-spin coupling constants. In solution, flavodoxin consists of a five-stranded parallel β-sheet and four α-helices. Residues 3–9, 32–36, 52–58, 87–96, and 123–128 are involved in the β-sheet whereas the a-helical regions comprise residues 13–28, 69–76, 104–114, and 134–148. Several proton resonances of the bound flavin mononucleotide cofactor have been assigned. NOE contacts between the prosthetic group and the apoprotein have been detected.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1993.tb17746.x

Homonuclear and heteronuclear NMR studies of oxidized Desulfovibrio vulgaris flavodoxin. Sequential assignments and identification of secondary structure elements.

G. Paul Curley

Papers

Redox and flavin‐binding properties of recombinant flavodoxin from Desulfovibrio vulgaris (Hildenborough)

Homonuclear and heteronuclear NMR studies of oxidized Desulfovibrio vulgaris flavodoxin. Sequential assignments and identification of secondary structure elements.