Sharon L. Davy

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The water-soluble cytochrome b557 from the photosynthetic bacterium Rhodobacter capsulatus was purified and shown to have the properties of the iron-storage protein bacterioferritin. The molecular mass of R. capsulatus bacterioferritin is 428 kDa and it is composed of a single type of 18-kDa subunit. The N-terminal amino acid sequence of the(More)
The solution structure of the 64 amino acid Fe4S4 ferredoxin I from Desulfovibrio africanus has been determined using two-dimensional 1H NMR spectroscopy. Sequence-specific assignments were obtained for 59 amino acid residues and the structure determined with the program DIANA on the basis of 549 nuclear Overhauser enhancement (NOE) upper distance limits,(More)
PrrC from Rhodobacter sphaeroides provides the signal input to a two-component signal transduction system that senses changes in oxygen tension and regulates expression of genes involved in photosynthesis (Eraso, J.M. and Kaplan, S. (2000) Biochemistry 39, 2052-2062; Oh, J.-I. and Kaplan, S. (2000) EMBO J. 19, 4237-4247). It is also a homologue of(More)
Ni2+ affinity columns are widely used for protein purification, but they carry the risk that Ni2+ ions may bind to the protein, either adventitiously or at a physiologically important site. Dialysis against ethylenediaminetetraacetic acid (EDTA) is normally used to remove metal ions bound adventitiously to proteins; however, this approach does not always(More)
The nucleotide sequence of the Rhodobacter capsulatus bacterioferritin gene (bfr) was determined and found to encode a protein of 161 amino acids with a predicted molecular mass of 18,174 Da. The molecular mass of the purified protein was estimated to be 18,176. +/ 0.80 Da by electrospray mass spectrometry. The bfr was introduced into an expression vector,(More)
Desulfovibrio africanus ferredoxin I was studied by magnetic circular dichroism and 1H-NMR spectroscopies. These showed the presence of histidine and tryptophan, in contrast to the previously reported amino-acid sequence (Bruschi and Hatchikian (1982) Biochimie 64, 503-507). This was redetermined and the revised sequence shown to contain both histidine and(More)
1D and 2D 1H NMR studies of the Fe4S4 cluster containing ferredoxin I from Desulfovibrio africanus have been carried out with the aim of determining the geometry of the cluster linkages with the 4 Cys side chains that bind the cluster. This required the Cys beta CH resonances of the oxidised protein to be sequence-specifically and stereo-specifically(More)
Dicluster ferredoxins (Fds) from Sulfolobus acidocaldarius and Desulfovibrio africanus (FdIII) have been studied using 1H NMR. Both wild-type proteins contain a [3Fe-4S]+/0 and a [4Fe-4S]2+/+ cluster as isolated. The [4Fe-4S]2+/+ cluster (cluster II) is bound by cysteine residues arranged in a classic ferredoxin motif: CysI-(Xaa)2-CysII-(Xaa)2-CysIII-(Xaa)(More)
 Assignment of the resonance Raman (RR) spectrum of Ni(II)-substituted azurin II from Alcaligenes xylosoxidans (NCIMB 11015) using Ni isotope substitution reveals an anomalously low Ni-S(Cys) stretching frequency of 349 cm–1, suggesting the presence of significant axial-ligand bonding interactions. The X-ray crystal structure of Ni(II)-substituted azurin(More)
Desulfovibrio africanus ferredoxin III (Da FdIII) contains one [4Fe-4S](2+/1+) cluster and one [3Fe-4S](1+/0) cluster, bound by seven Cys residues, in which the [3Fe-4S] cluster is co-ordinated by the unusual sequence, Cys(11)-Xaa-Xaa-Asp(14)-Xaa-Xaa-Cys(17)-Xaa(n)-Cys(51)-Glu. The [3Fe-4S] core of this ferredoxin is so far unique in showing rapid(More)