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D A Bryant

Publications and source records attributed to D A Bryant.

At least 37 records · Page 2Linked to original sources
PubMed1997

Low-temperature-induced desaturation of fatty acids and expression of desaturase genes in the cyanobacterium Synechococcus sp. PCC 7002.

Changes in response to temperature of lipid classes, fatty acid composition and mRNA levels for acyl-lipid desaturase genes were studied in the marine unicellular cyanobacterium, Synechococcus sp. PCC 7002. The degree of unsaturation of C18 fatty acids increased in cells grown at lower temperature for all lipid classes, and omega 3 desaturation occurred specifically in cells grown at low temperature. While the level of 18:1(9) fatty acids declined, desaturation at the omega 3 position of C18 fatty acids increased gradually during a 12-h period after a temperature shift-down to 22 degrees C. However, the mRNA levels of the desA (delta 12 desaturase), desB (omega 3 desaturase) and desC (delta 9 desaturase) genes increased within 15 min after a temperature shift-down to 22 degrees C; the desaturase gene mRNA levels also rapidly declined within 15 min after a temperature shift-up to 38 degrees C. Therefore, the elevation of mRNA levels for the desaturase genes is not the rate-limiting event for the increased desaturation of membrane lipids after a temperature shift-down. The rapid, low-temperature-induced changes in mRNA levels occurred even when cells were grown under light-limiting conditions for which the growth rates at 22 degrees C and 38 degrees C were identical. These studies indicate that the ambient growth temperature, and not some other growth rate-related process, regulates the expression of acyl lipid desaturation in this cyanobacterium.

Cold Temperature↗
PubMed1997

Temperature-regulated mRNA accumulation and stabilization for fatty acid desaturase genes in the cyanobacterium Synechococcus sp. strain PCC 7002.

Cyanobacteria acclimate to low-temperature conditions by desaturating their membrane lipids. The desB (omega 3 desaturase) and desC (delta 9 desaturase) genes of Synechococcus sp. strain PCC 7002 were cloned and characterized, and the expression of the desA (delta 12 desaturase), desB and desC genes was studied as a function of temperature. The steady-state mRNA abundance for the desA gene was threefold higher in cells grown at 22 degrees C than in cells grown at 38 degrees C. desB transcripts were not detected at 38 degrees C, but were abundant in cells grown at 22 degrees C. Levels of desC mRNA were similar at both growth temperatures. The mRNA levels of each desaturase gene increased within 15 min of a temperature shift-down to 22 degrees C, and mRNA levels recovered within 15 min after a shift-up to 38 degrees C. The cold-induced accumulation of transcripts from the desA and desB genes was suppressed by the addition of chloramphenicol, but the transient elevation of the desC transcript levels at 22 degrees C was not affected by chloramphenicol. The half-lives of the desA and desB mRNAs were significantly longer in cells grown at 22 degrees C than in cells grown at 38 degrees C, but the desC mRNA had a similar half-life at both temperatures. These studies reveal three patterns of temperature regulation for the desaturase genes, whose expression is tightly controlled by a combination of mRNA synthesis and stabilization. These studies demonstrate that elevation of desaturase mRNA levels is not the rate-limiting event during the low-temperature acclimation of cyanobacteria.

Blotting, Northern↗
PubMed1997

Molecular systematic studies of eubacteria, using sigma70-type sigma factors of group 1 and group 2.

Sigma factors of the sigma70 family were used as a phylogenetic tool to compare evolutionary relationships among eubacteria. Several new sigma factor genes were cloned and sequenced to increase the variety of available sequences. Forty-two group 1 sigma factor sequences of various species were analyzed with the help of a distance matrix method to establish a phylogenetic tree. The tree derived by using sigma factors yielded subdivisions, including low-G+C and high-G+C gram-positive bacteria, cyanobacteria, and the alpha, beta, gamma, and delta subdivisions of proteobacteria, consistent with major bacterial groups found in trees derived from analyses with other molecules. However, some groupings (e.g., the chlamydiae, mycoplasmas, and green sulfur bacteria) are found in different positions than for trees obtained by using other molecular markers. A direct comparison to the most extensively used molecule in systematic studies, small-subunit rRNA, was made by deriving trees from essentially the same species set and using similar phylogenetic methods. Differences and similarities based on the two markers are discussed. Additionally, 31 group 2 sigma factors were analyzed in combination with the group 1 proteins in order to detect functional groupings of these alternative sigma factors. The data suggest that promoters recognized by the major vegetative sigma factors of eubacteria will contain sequence motifs and spacing very similar to those for the sigma70 sigma factors of Escherichia coli.

Amino Acid Sequence↗
PubMed1996

Modified ligands to FA and FB in photosystem I. Proposed chemical rescue of a [4Fe-4S] cluster with an external thiolate in alanine, glycine, and serine mutants of PsaC.

The FB and FA electron acceptors in Photosystem I (PS I) are [4Fe-4S] clusters ligated by cysteines provided by PsaC. In a previous study (Mehari, T., Qiao, F., Scott, M. P., Nellis, D., Zhao, J., Bryant, D., and Golbeck, J. H. (1995) J. Biol. Chem. 270, 28108-28117), we showed that when cysteines 14 and 51 were replaced with serine or alanine, the free proteins contained a S = 1/2, [4Fe-4S] cluster at the unmodified site and a mixed population of S = 1/2, [3Fe-4S] and S = 3/2, [4Fe-4S] clusters at the modified site. We show here that these mutant PsaC proteins can be rebound to P700-FX cores, resulting in fully functional PS I complexes. The low temperature EPR spectra of the C14XPsaC.PS I complexes (where X = S, A, or G) show the photoreduction of a wild-type FA cluster and a modified FB' cluster, the latter with g values of 2.115, 1.899, and 1.852 and linewidths of 110, 70, and 85 MHz. Since neither alanine nor glycine contains a suitable side group, an external thiolate provided by beta-mercaptoethanol has likely been recruited to supply the requisite ligand to the [4Fe-4S] cluster. The EPR spectrum of the C51SPsaC.PS I complex differs from that of the C51APsaC.PS I or C51GPsaC.PS I complexes by the presence of an additional set of resonances, which may be derived from the serine oxygen-ligated cluster. In all other mutant PS I complexes, a wild-type spin-coupled interaction spectrum appears when FA and FB are simultaneously reduced. Single turnover flash studies indicate approximately 50% efficient electron transfer to FA/FB in the C14SPsaC.PS I, C51SPsaC.PS I, C14GPsaC.PS I, and C51GPsaC.PS I mutants and less than 40% in the C14APsaC.PS I and C51APsaC.PS I mutants, compared with approximately 76% in the PS I core reconstructed with wild-type PsaC. These data are consistent with the measurements of the rates of cytochrome c6-NADP+ reductase activity, indicating lower rates in the alanine mutants. It is proposed that the chemical rescue of a [4Fe-4S] cluster with a recruited external thiolate at the modified site allows the mutant PsaC proteins to rebind to PS I and to function in forward electron transfer.

Alanine↗
PubMed1996

Characterization of a redox-active cross-linked complex between cyanobacterial photosystem I and its physiological acceptor flavodoxin.

A covalent complex between photosystem I and flavodoxin from the cyanobacterium Synechococcus sp. PCC 7002 was generated by chemical cross-linking. Laser flash-absorption spectroscopy indicates that the bound flavodoxin of this complex is stabilized in the semiquinone state and is photoreduced to the quinol form upon light excitation. The kinetics of this photoreduction process, which takes place in approximately 50% of the reaction centres, displays three exponential components with half-lives of 9 microsec, 70 microsec and 1 ms. The fully reduced flavodoxin subsequently recombines with P700+ with a t1/2 of 330 ms. A corresponding flavodoxin semiquinone radical signal is readily observed in the dark by room temperature electron paramagnetic resonance, which reversibly disappears upon illumination. In contrast, the light-induced reduction of oxidized flavodoxin can be observed only by first-flash experiments following excessive dark adaptation. In addition, the docking site of flavodoxin on photosystem I was determined by electron microscopy in combination with image analysis. Flavodoxin binds to the cytoplasmic side of photosystem I at a distance of 7 nm from the centre of the trimer and in close contact to a ridge formed by the subunits PsaC, PsaD and PsaE.

Binding Sites↗
PubMed1996

Interaction between photosystem I and flavodoxin from the cyanobacterium Synechococcus sp. PCC 7002 as revealed by chemical cross-linking.

The interaction between photosystem I (PS I) and flavodoxin from the cyanobacterium Synechococcus sp. PCC 7002 was investigated by covalent cross-linking in the presence of a hydrophilic cross-linker, N- ethyl-3-(3-diaminopropyl)carbodiimide. Under the experimental conditions employed, five distinct cross-linking products of flavodoxin and PS I subunits are formed. Immunoblot analyses show that these species are the result of cross-linking of flavodoxin to PsaC, PsaD, an unidentified low-molecular-mass PS I polypeptide, and a 15-kDa subunit. The latter has been indirectly identified as the PsaF subunit. Analysis of the interaction of flavodoxin with PS I from a psaE mutant indicates that the PsaE subunit is required for correct complex formation between flavodoxin and PS I, although this subunit is not directly cross-linked to flavodoxin. In addition, the cross-linking products of PsaD with PsaC and PsaL, and PsaE with PsaF, are observed. The covalent complex of flavodoxin and PS I is shown to be fully inhibited with respect to electron transfer to soluble flavodoxin, ferredoxin or ferredoxin:NADP+ oxidoreductase.

Binding Sites↗
PubMed1996

Characterization of csmB genes, encoding a 7.5-kDa protein of the chlorosome envelope, from the green sulfur bacteria Chlorobium vibrioforme 8327D and Chlorobium tepidum.

The csmB gene, encoding the 7.5-kDa "Gerola-Olson" protein of chlorosomes, has been cloned and sequenced from the green sulfur bacteria Chlorobium vibrioforme strain 8327D and Chlorobium tepidum. Two potential start codons were identified, and the csmB gene may be translated into a preprotein with an amino-terminal extension. Two forms of the mature CsmB protein (74 or 75 amino acids in length) were identified that differ by the presence or absence of a methionine residue at the amino terminus. The csmB gene of Chl. tepidum is transcribed as an abundant monocistronic mRNA of approximately 350 nucleotides; primer extension mapping of the 5' endpoint of the csmB mRNA suggests there is strong similarity between the csmB promoter and the sigma70 promoters of Escherichia coli. The CsmB protein of Chl. tepidum was overproduced as a histidine-tagged fusion protein in E. coli, purified to homogeneity by Ni2+ chelation affinity chromatography, and used to raise polyclonal antibodies in rabbits. Protease susceptibility mapping and agglutination experiments with isolated chlorosomes using anti-CsmB antibodies indicate that the CsmB protein is a component of the chlorosome envelope.

Amino Acid Sequence↗
PubMed1996

Colonic epithelial lymphocytosis associated with an epidemic of chronic diarrhea.

The term Brainerd diarrhea has been applied to outbreaks of chronic watery diarrhea of unknown etiology characterized by acute onset and prolonged duration. Our aim was to describe the histologic changes in gastrointestinal biopsy specimens from patients with Brainerd diarrhea. We examined 52 colonic and 12 small bowel biopsy specimens from 22 patients who were involved in an outbreak of Brainerd diarrhea that was linked to the water supply of a cruise ship visiting the Galapagos Islands. Small bowel biopsy specimens from seven patients were histologically normal. One patient had a duodenal biopsy specimen that resembled celiac sprue. Colonic biopsy specimens from 20 patients revealed surface epithelial lymphocytosis without distortion of mucosal architecture, surface degenerative changes, or thickened subepithelial collagen plates. The degree of surface epithelial lymphocytosis was greater than that seen in control groups of persons with normal colons, acute colitis, and ulcerative colitis (p < 0.001), similar to that seen with collagenous colitis, and less than that seen with lymphocytic colitis (p < 0.001). Three patients showed focal active colitis similar to that described in acute infectious-type colitis in addition to the epithelial lymphocytosis. Two patients had colonic biopsy specimens that were histologically normal. In summary, histologic abnormalities in the small bowel are generally absent in Brainerd diarrhea. Colonic biopsy specimens in Brainerd diarrhea frequently show epithelial lymphocytosis similar to that seen in collagenous and lymphocytic colitis. Although currently Brainerd diarrhea can be diagnosed only with epidemiologic data indicating an epidemic and a point source, the lack of surface degenerative changes and the relatively lower lymphocyte counts seen in our cases of Brainerd diarrhea may serve to distinguish it from lymphocytic colitis, and the lack of a thickened subepithelial collagen plate distinguishes it from collagenous colitis.

Adult↗
PubMed1996

Characterization of psaI and psaL mutants of Synechococcus sp. strain PCC 7002: a new model for state transitions in cyanobacteria.

The psaI and psaL genes were characterized from the cyanobacterium Synechococcus sp. strain PCC 7002. The gene organization was different from that reported for other cyanobacteria with psaI occurring upstream and being divergently transcribed from the psaL gene. Mutants lacking PsaI or PsaL were generated by interposon mutagenesis and characterized physiologically and biochemically. Mutant strains PR6307 (delta psaI), PR6308 (psaI-) and PR6309 (psaL-) had doubling times similar to that of the wild type under both high- and low-intensity white light, but all grew more slowly than the wild type in green light. Only monomeric photosystem I (PS I) complexes could be isolated from each mutant strain when Triton X-100 was used to solubilize thylakoid membranes; however, approximately 10% of the PS I complexes from the psaI mutants, but not the psaL mutant, could be isolated as trimers when n-dodecyl beta-D-maltoside was used. Compositional analyses of the mutant PS I complexes indicate that the presence of PsaL is required for trimer formation or stabilization and that PsaI plays a role in stabilizing the binding of both PsaL and PsaM to the PS I complex. Strain PR6309 (psaL-) was capable of performing a state 2 to state 1 transition approximately three times more rapidly than the wild type. Because the monomeric PS I complexes of this mutant should be capable of diffusing more rapidly than trimeric complexes, these data suggest that PS I complexes rather than phycobilisomes might move during state transitions. A "mobile-PS I" model for state transitions that incorporates these ideas is discussed.

Amino Acid Sequence↗
PubMed1995

Modified ligands to FA and FB in photosystem I. I. Structural constraints for the formation of iron-sulfur clusters in free and rebound PsaC.

Cysteines 14, 21, 34, 51, or 58 in PsaC of photosystem I (PS I) were replaced with aspartic acid (C21D and C58D), serine (C14S, C34S, and C51S), and alanine (C14A, C34A, and C51A). When free in solution, the C34S and C34A holoproteins contained two S = 1/2 ground state [4Fe-4S] clusters; all other mutant proteins contained [3Fe-4S] clusters and [4Fe-4S] clusters; in addition, there was evidence in C14S, C51S, C14A, and C51A for high spin (S = 3/2) [4Fe-4S] clusters, presumably in the modified site. These findings are consistent with the assignment of C14, C21, C51, and C58, but not C34, as ligands to FA and FB. The [4Fe-4S] clusters in the unmodified sites in C14S, C51S, C14A, and C51A remained highly electronegative, with Em values ranging from -495 to -575 mV. The [3Fe-4S] clusters in the modified sites were driven 400 to 450 mV more oxidizing than the native [4Fe-4S] clusters, with Em values ranging from -98 mV to -171 mV. A C14D/C51D double mutant contains [3Fe-4S] and S = 1/2 [4Fe-4S] clusters, showing that the 3Cys.1Asp motif is also able to accommodate a low spin cubane. When C34S, C34A, C14S, C51S, C14A, and C51A were rebound to P700-FX cores, electron transfer to FA/FB was regained, but functional reconstitution has not yet been achieved for C21D, C58D, or C14D/C51D. These data imply that PsaC requires two iron-sulfur clusters to refold, one of which must be a cubane. Since two [4Fe-4S] clusters are found in all reconstituted PS I complexes, the presence of two cubanes in free PsaC may be a necessary precondition for binding to P700-FX cores.

Amino Acid Sequence↗
PubMed1995

Modified ligands to FA and FB in photosystem I. II. Characterization of a mixed ligand [4Fe-4S] cluster in the C51D mutant of PsaC upon rebinding to P700-Fx cores.

A Photosystem I (PS I) complex reconstituted with PsaC-C51D (aspartate in lieu of cysteine in position 51) shows light-induced EPR signals with g values, line widths, and photoreduction behavior characteristic of FB. Contrary to an earlier report, a [3Fe-4S] cluster was not located in the reconstituted PS I complex. Instead, a second set of resonances with g values of 2.044, 1.942, and 1.853 becomes EPR-visible when the C51D-PS I complex is measured at 4.2 K. This fast relaxing center, termed FA' is likely to represent a [4Fe-4S] cluster in the mixed ligand (3Cys.1Asp) site. Redox studies show that the Em of FA' and FB are -630 mV and -575 mV, respectively. Room temperature optical studies support the presence of two functioning electron acceptors subsequent to Fx, and NADP+ photoreduction rates mediated by ferredoxin and flavodoxin are nearly equivalent to the wild type. In addition to [3Fe-4S] clusters and S = 1/2 ground state [4Fe-4S] clusters, the free PsaC-C51D protein shows resonances near g = 5.5, which may represent a population of high spin (S = 3/2) [4Fe-4S] clusters in the mixed ligand FA' site. Similar to the C14D-PS I mutant complex, it is proposed that the P700-Fx core selectively rebinds those free PsaC-C51D proteins that contain two [4Fe-4S] clusters. These studies show that primary photochemistry and electron transfer rates in PS I are relatively unaffected by the presence of a highly reducing, mixed ligand cluster in the FA' site.

Aspartic Acid↗
PubMed1995

Evidence for a mixed-ligand [4Fe-4S] cluster in the C14D mutant of PsaC. Altered reduction potentials and EPR spectral properties of the FA and FB clusters on rebinding to the P700-FX core.

PsaC-C14D (cysteine 14 replaced by aspartic acid) contains a [3Fe-4S] and a [4Fe-4S] cluster in the FB and FA sites of the free protein [Yu, L., Zhao, J., Lu, W., Bryant, D. A., & Golbeck, J. H. (1993) Biochemistry 32, 8251-8258]. When PsaC-C14D is rebound to a photosystem I (PS I) core, the g-values of 2.043, 1.939, and 1.853 appear similar to FA in a wild-type PS I complex [Zhao, J. D., Li, N., Warren, P. V., Golbeck, J. H., & Bryant, D. A. (1992) Biochemistry 31, 5093-5099]. The reconstituted PsaC-C14D-PS I complex does not contain a [3Fe-4S] cluster; rather, a set of resonances with a rhombic line shape, a gav of approximately 1.97, and broad line widths indicate the presence of a mixed-ligand [4Fe-4S] cluster, termed FB', in the aspartate site. Both FA and FB' become photoreduced at 15 K, and show an interaction spectrum when reduced within the same reaction center. An electrochemical redox study shows that FA and FB' titrate with midpoint potentials near -600 mV at pH 10.0. Single-turnover flash experiments indicate that FA and FB' function as efficient electron acceptors at room temperature, and NADP+ photoreduction rates are about 70% that of a reconstituted PsaC-PS I complex. A population of S = 3/2, [4Fe-4S] clusters was tentatively identified in the free PsaC-C14D protein by characteristic EPR resonances in the g = 5.3 region.(ABSTRACT TRUNCATED AT 250 WORDS)

Chlorophyll↗
PubMed1994

Spectroscopic studies of phycobilisome subcore preparations lacking key core chromophores: assignment of excited state energies to the Lcm, beta 18 and alpha AP-B chromophores.

Chromophore absorption and emission characteristics of the alpha AP-B, beta 18 and Lcm (large core-membrane linker) chromopeptides within the phycobilisome core are investigated using genetically engineered strains of Synechococcus sp. PCC 7002. Steady-state and time-resolved emission were used to examine energy transfer in subcore preparations from the wild-type organism and two mutants. Low-temperature (77 K) emission spectra were also measured for intact phycobilisomes from the wild-type and five mutant strains. Mutants retaining either the alpha AP-B subunit or the unaltered Lcm chromophore resulted in only small changes in the low-temperature emission spectra, while retention of only the beta 18 subunit resulted in blue-shifted emission spectra. The Lcm chromophore has a room-temperature absorption maximum at 675 nm. In phycobilisomes at 77 K the alpha AP-B and Lcm chromophores emit at 682-683 nm, and they are the best candidates for long-wavelength emitters also at room temperature. Overlap of these emission spectra with the absorption of chlorophyll a in the associated thylakoid membrane plays a significant role in excitation transfer from the antenna complexes in cyanobacteria.

Bacterial Proteins↗
PubMed1994

1H and 15N NMR assignments of PsaE, a photosystem I subunit from the cyanobacterium Synechococcus sp. strain PCC 7002.

PsaE is a highly conserved, water-soluble protein of the photosystem I reaction center complexes of cyanobacteria, algae, and green plants. Along with the PsaC and PsaD proteins, the PsaE protein binds to the stromal surface of photosystem I and is required for cyclic electron transport in Synechococcus sp. strain PCC 7002 [Yu, L., Zhao, J., Mühlenhoff, U., Bryant, D.A., & Golbeck, J.H. (1993) Plant Physiol. 103, 171-180]. The psaE gene from this cyanobacterium encodes a mature protein of 69 amino acid residues and has recently been overexpressed in Escherichia coli [Zhao, J., Snyder, W.B., Mühlenhoff, U., Rhiel, E., Warren, P. V., Golbeck, J. H., & Bryant, D. A. (1993) Mol. Microbiol. 9, 183-194]. By using both unlabeled and uniformly 15N-labeled protein in a series of two- and three-dimensional NMR experiments, complete 1H and 15N amide resonance assignments were made. The major secondary structural element of PsaE is a five-stranded antiparallel beta-sheet. The five strands extend as follows: beta A, residues 7-10; beta B, residues 21-26; beta C, residues 36-39; beta D, residues 57-60; and beta E, residues 65-68. The topology is represented by (+1, +1, +1, -4x); it brings the first and last strands, and consequently the N- and C-termini, together. The protein has an extensive hydrophobic core organized around a conserved phenylalanine residue (Phe-40); another of its distinctive features is a segment extending from residue 42 to residue 56 devoid of dipolar contacts with the beta-sheet. The pK1/2 of the sole histidine residue (His-63) was determined to be 5.4.

Amino Acid Sequence↗
PubMed1994

Three-dimensional solution structure of PsaE from the cyanobacterium Synechococcus sp. strain PCC 7002, a photosystem I protein that shows structural homology with SH3 domains.

PsaE is a 69 amino acid polypeptide from photosystem I present on the stromal side of the thylakoid membrane. The three-dimensional solution structure of this protein from the cyanobacterium Synechococcus sp. strain PCC 7002 was determined at pH 5.8 and room temperature using over 900 experimental restraints derived from two- and three-dimensional NMR experiments. The structure is comprised of a well-defined five-stranded beta-sheet with (+1, +1, +1, -4 alpha) topology. There is no helical region except for a single turn of 3(10) helix between the beta D and beta E strands. PsaE also exhibits a large unrestrained loop spanning residues 42-56. A comparison to known protein structures revealed similarity with the Src homology 3 (SH3) domain, a membrane-associated protein involved in signal transduction in eukaryotes. The match is remarkable as 47 of the alpha-carbons of PsaE can be superimposed onto those of the SH3 domain from chicken brain alpha-spectrin with a root-mean-square deviation of 2.3 A. Although the amino acid sequences have low identity and the loops are different in both proteins, the topology of the beta-sheet and the 3(10) turn is conserved. SH3 domains from other sources show a similar structural homology. The structure of PsaE was used to suggest approaches for elucidating its roles within photosystem I.

Amino Acid Sequence↗
PubMed1993

Characterization of the [3Fe-4S] and [4Fe-4S] clusters in unbound PsaC mutants C14D and C51D. Midpoint potentials of the single [4Fe-4S] clusters are identical to FA and FB in bound PsaC of photosystem I.

In a previous paper we showed that the C51D mutant of PsaC contains a [3Fe-4S] cluster in the FA site and a [4Fe-4S] cluster in the FB site and that the C14D mutant contains an uncharacterized cluster in the FB site and a [4Fe-4S] cluster in the FA site [Zhao, J. D., Li, N., Warren, P. V., Golbeck, J. H., & Bryant, D. A. (1992) Biochemistry 31, 5093-5099]. In this paper we describe the electrochemical and electron spin resonance properties of the recombinant C14D and C51D holoproteins after in vitro reinsertion of the iron-sulfur clusters. Unbound PsaC shows no significant resonances in the oxidized state, but the unbound C14D and C51D mutant proteins show an intense set of resonances at g approximately 2.02 and 1.99 characteristic of an oxidized [3Fe-4S]1+/0 cluster. The Em' values for the [3Fe-4S]1+/0 clusters in C14D (FB*) and C51D (FA*) are -98 mV, and both represent one-electron transfers. After reduction with dithionite at pH 10.0, wild-type PsaC shows a broad set of resonances resulting from the superposition of FA- and FB- characterized by a low-field peak at an apparent g value of 2.051 and a high-field trough at an apparent g value of 1.898. The FB resonances in C51D were slightly narrower, with a low-field peak at an apparent g value of 2.039 and high-field trough at an apparent g value of 1.908.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Proteins↗