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The Ferredoxin-Like Protein FerR Regulates PrbP Activity in Liberibacter asiaticus. Appl Environ Microbiol 2019; 85:AEM.02605-18. [PMID: 30552192 DOI: 10.1128/aem.02605-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 12/08/2018] [Indexed: 12/26/2022] Open
Abstract
In Liberibacter asiaticus, PrbP is an important transcriptional accessory protein that regulates gene expression through interactions with the RNA polymerase β-subunit and a specific sequence on the promoter region. The constitutive expression of prbP observed upon chemical inactivation of PrbP-DNA interactions in vivo indicated that the expression of prbP was not autoregulated at the level of transcription. This observation suggested that a modulatory mechanism via protein-protein interactions may be involved. In silico genome association analysis identified FerR (CLIBASIA_01505), a putative ferredoxin-like protein, as a PrbP-interacting protein. Using a bacterial two-hybrid system and immunoprecipitation assays, interactions between PrbP and FerR were confirmed. In vitro transcription assays were used to show that FerR can increase the activity of PrbP by 16-fold when present in the PrbP-RNA polymerase reaction mixture. The FerR protein-protein interaction surface was predicted by structural modeling and followed by site-directed mutagenesis. Amino acids V20, V23, and C40 were identified as the most important residues in FerR involved in the modulation of PrbP activity in vitro The regulatory mechanism of FerR abundance was examined at the transcription level. In contrast to prbP of L. asiaticus (prbP Las), mRNA levels of ferR of L. asiaticus (ferR Las) are induced by an increase in osmotic pressure. The results of this study revealed that the activity of the transcriptional activator PrbPLas is modulated via interactions with FerRLas The induction of ferR Las expression by osmolarity provides insight into the mechanisms of adjusting gene expression in response to host environmental signals in L. asiaticus IMPORTANCE The rapid spread and aggressive progression of huanglongbing (HLB) in the major citrus-producing areas have raised global recognition of and vigilance to this disease. As a result, the causative agent, Liberibacter asiaticus, has been investigated from various perspectives. However, gene expression regulatory mechanisms that are important for the survival and persistence of this intracellular pathogen remain largely unexplored. PrbP is a transcriptional accessory protein important for L. asiaticus survival in the plant host. In this study, we investigated the interactions between PrbP in L. asiaticus (PrbPLas) and a ferredoxin-like protein (FerR) in L. asiaticus, FerRLas We show that the presence of FerR stabilizes and augments the activity of PrbPLas In addition, we demonstrate that the expression of ferR is induced by increases in osmolarity in Liberibacter crescens Altogether, these results suggest that FerRLas and PrbPLas may play important roles in the regulation of gene expression in response to changing environmental signals during L. asiaticus infection in the citrus host.
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Segal HM, Spatzal T, Hill MG, Udit AK, Rees DC. Electrochemical and structural characterization of Azotobacter vinelandii flavodoxin II. Protein Sci 2017; 26:1984-1993. [PMID: 28710816 PMCID: PMC5606536 DOI: 10.1002/pro.3236] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/08/2017] [Accepted: 07/10/2017] [Indexed: 01/07/2023]
Abstract
Azotobacter vinelandii flavodoxin II serves as a physiological reductant of nitrogenase, the enzyme system mediating biological nitrogen fixation. Wildtype A. vinelandii flavodoxin II was electrochemically and crystallographically characterized to better understand the molecular basis for this functional role. The redox properties were monitored on surfactant-modified basal plane graphite electrodes, with two distinct redox couples measured by cyclic voltammetry corresponding to reduction potentials of -483 ± 1 mV and -187 ± 9 mV (vs. NHE) in 50 mM potassium phosphate, 150 mM NaCl, pH 7.5. These redox potentials were assigned as the semiquinone/hydroquinone couple and the quinone/semiquinone couple, respectively. This study constitutes one of the first applications of surfactant-modified basal plane graphite electrodes to characterize the redox properties of a flavodoxin, thus providing a novel electrochemical method to study this class of protein. The X-ray crystal structure of the flavodoxin purified from A. vinelandii was solved at 1.17 Å resolution. With this structure, the native nitrogenase electron transfer proteins have all been structurally characterized. Docking studies indicate that a common binding site surrounding the Fe-protein [4Fe:4S] cluster mediates complex formation with the redox partners Mo-Fe protein, ferredoxin I, and flavodoxin II. This model supports a mechanistic hypothesis that electron transfer reactions between the Fe-protein and its redox partners are mutually exclusive.
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Affiliation(s)
- Helen M Segal
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125
| | - Thomas Spatzal
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125
| | - Michael G Hill
- Division of Chemistry, Occidental College, Los Angeles, California, 90041
| | - Andrew K Udit
- Division of Chemistry, Occidental College, Los Angeles, California, 90041
| | - Douglas C Rees
- Division of Chemistry and Chemical Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, 91125
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Zumft WG. The molecular basis of biological dinitrogen fixation. STRUCTURE AND BONDING 2007. [DOI: 10.1007/bfb0116518] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Hallenbeck PC, Gennaro G. Stopped-flow kinetic studies of low potential electron carriers of the photosynthetic bacterium, Rhodobacter capsulatus: ferredoxin I and NifF. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1365:435-42. [PMID: 9711296 DOI: 10.1016/s0005-2728(98)00096-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The kinetics of electron-transfer reactions involving nif-specific proteins from Rhodobacter capsulatus; ferredoxin I, NifF, Fe-protein of nitrogenase and dithionite were studied using stopped-flow spectrophotometry. Kinetic evidence was obtained for the formation of a tight (0.44 microM) complex between NifF and Fe-protein. Under the same conditions, FdI interacted only weakly (Kd > 325 microM) with Fe-protein. There was no evidence for complex formation between NifF and FdI since the reaction NifFSQ + FdIred had a bimolecular rate constant of 12.5 +/- 1.2 x 10(3) M-1 s-1. These results suggest that NifF, which is present in only small quantities in the cell, can make a significant contribution to the overall rate of nitrogen fixation due its high reactivity with Fe-protein. Moreover, the apparent lack of specific interaction between NifF and FdI suggest that they act in vivo in parallel to reduce Fe-protein and not in series.
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Affiliation(s)
- P C Hallenbeck
- Département de Microbiologie et Immunologie, Université de Montréal, Que., Canada.
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6
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Anderson BM, Wise DJ, Anderson CD. Azotobacter vinelandii glucose 6-phosphate dehydrogenase properties of NAD- and NADP-linked reactions. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1340:268-76. [PMID: 9252113 DOI: 10.1016/s0167-4838(97)00057-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glucose 6-phosphate oxidation, catalyzed by purified Azotobacter vinelandii glucose 6-phosphate dehydrogenase, was studied with respect to the selective utilization of NAD, NADP, thionicotinamide adenine dinucleotide or thionicotinamide adenine dinucleotide phosphate as coenzyme. A sigmoidal relationship was observed for the effect of substrate concentration on initial velocities when either NAD, NADP or thionicotinamide adenine dinucleotide was used as coenzyme, with N values from the Hill equation equalling 2.0, 1.7, and 1.7, respectively. The thionicotinamide analogs of NAD and NADP both functioned as coenzyme-competitive inhibitors of the enzyme-catalyzed NAD- and NADP-linked reactions. A dual wavelength assay, using a combination of NADP and thio-NAD, was established and was used to demonstrate that increasing glucose 6-phosphate concentration did not change the enzyme preference for the coenzyme form used. Sigmoidal relationships were observed for reduction of both dinucleotides, and N values were the same as those observed when each dinucleotide was studied as the only coenzyme form present in reaction mixtures. Using the dual wavelength assay, inhibition by isocitrate, 6-phosphogluconate, ATP, and palmitoyl-CoA was shown to be equally effective in both NAD- and NADP-linked reactions. An enzyme activator, glucosamine 6-phosphate, altered the glucose 6-phosphate sigmoidicity through activation at low substrate concentrations.
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Affiliation(s)
- B M Anderson
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg 20461-0308, USA.
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7
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Allen RM, Chatterjee R, Ludden PW, Shah VK. The requirement of reductant for in vitro biosynthesis of the iron-molybdenum cofactor of nitrogenase. J Biol Chem 1996; 271:4256-60. [PMID: 8626771 DOI: 10.1074/jbc.271.8.4256] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A source of reductant is routinely added to the in vitro iron-molybdenum cofactor (FeMo-co) synthesis assay, although a requirement for reductant has not been established. This report demonstrates that the addition of reductant to the in vitro FeMo-co synthesis system is not required when Azotobacter vinelandii cell-free extract is prepared in buffer that lacks added reductant. The addition of reductant is required, however, if the A. vinelandii cell-free extract is chemically oxidized prior to addition to the assay. These results might suggest that extracts of A. vinelandii contain a physiological source of reductant that functions in the in vitro synthesis of FeMo-co. It is possible that the proteins required for FeMo-co biosynthesis (e.g. NIFNE and dinitrogenase reductase) are at the appropriate redox state to function in the in vitro reaction in the extract that is free of added reductant but not in the chemically oxidized extract. It is also possible that dinitrogenase reductase and/or NIFNE (both Fe-S proteins required for FeMo-co synthesis) might catalyze the reductant-dependent reaction for FeMo-co synthesis. Dithionite, Ti(III) citrate, and NADH are able to serve as the source of reductant for in vitro FeMo-co biosynthesis.
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Affiliation(s)
- R M Allen
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison, 53706, USA
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Affiliation(s)
- C Sasikala
- Department of Botany, Osmania University, Hyderabad, India
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9
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Site-directed mutagenesis of Azotobacter vinelandii ferredoxin I. Changes in [4Fe-4S] cluster reduction potential and reactivity. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54675-5] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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10
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Brostedt E, Nordlund S. Purification and partial characterization of a pyruvate oxidoreductase from the photosynthetic bacterium Rhodospirillum rubrum grown under nitrogen-fixing conditions. Biochem J 1991; 279 ( Pt 1):155-8. [PMID: 1930134 PMCID: PMC1151561 DOI: 10.1042/bj2790155] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A pyruvate oxidoreductase with the capacity to support pyruvate-dependent nitrogenase activity in vitro has been purified from the photosynthetic bacterium Rhodospirillum rubrum. The enzyme requires CoA for activity and is irreversibly inactivated by oxygen. The molecular properties and Km values for the substrates have been studied. In supporting nitrogenase activity addition of ferredoxin is required. Overall the enzyme is similar to the nif-specific pyruvate: flavodoxin oxidoreductase purified from Klebsiella pneumoniae.
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Affiliation(s)
- E Brostedt
- Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
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Page WJ, Knosp O. Hyperproduction of Poly-β-Hydroxybutyrate during Exponential Growth of
Azotobacter vinelandii
UWD. Appl Environ Microbiol 1989; 55:1334-9. [PMID: 16347925 PMCID: PMC202867 DOI: 10.1128/aem.55.6.1334-1339.1989] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transformation of
Azotobacter vinelandii
UW with
A. vinelandii
113 DNA resulted in the formation of rifampin-resistant colonies, 13% of which also inherited a previously unrecognized mutation in the respiratory NADH oxidase. These transformants produced colonies with a white-sectored phenotype after prolonged incubation. Cells from these sectors were separated and purified by streaking and were named UWD. The dense white phenotype was due to the production of a large amount of poly-β-hydroxybutyrate during the exponential growth of strain UWD. The polymer accounted for 65 or 75% of the cell dry weight after 24 h of incubation of cultures containing glucose and either ammonium acetate or N
2
, respectively, as the nitrogen source. Under the same conditions, strain UW cells contained 22 to 25% poly-β-hydroxybutyrate, but O
2
-limited growth was required for these optimal production values. Polymer production was not dependent on O
2
limitation in strain UWD, but the efficiency of conversion of glucose to poly-β-hydroxybutyrate was enhanced in O
2
-limited cultures. Conversion efficiencies were >0.25 and 0.33 mg of poly-β-hydroxybutyrate per mg of glucose consumed under vigorous- and low-aeration conditions, respectively, compared with an efficiency of 0.05 achieved by strain UW. Strain UWD, therefore, appeared to from poly-β-hydroxybutyrate under novel conditions, which may be useful in designing new methods for the industrial production of biodegradable plastics.
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Affiliation(s)
- W J Page
- Department of Microbiology, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
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Martin AE, Burgess BK, Iismaa SE, Smartt CT, Jacobson MR, Dean DR. Construction and characterization of an Azotobacter vinelandii strain with mutations in the genes encoding flavodoxin and ferredoxin I. J Bacteriol 1989; 171:3162-7. [PMID: 2722744 PMCID: PMC210031 DOI: 10.1128/jb.171.6.3162-3167.1989] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Flavodoxin and ferredoxin I have both been implicated as components of the electron transport chain to nitrogenase in the aerobic bacterium Azotobacter vinelandii. Recently, the genes encoding flavodoxin (nifF) and ferredoxin I (fdxA) were cloned and sequenced and mutants were constructed which are unable to synthesize either flavodoxin (DJ130) or ferredoxin I (LM100). Both single mutants grow at wild-type rates under N2-fixing conditions. Here we report the construction of a double mutant (DJ138) which does not synthesize either flavodoxin or ferredoxin I. When plated on ammonium-containing medium, this mutant had a very small colony size when compared with the wild type, and in liquid culture with ammonium, this double mutant grew three times slower than the wild type or single mutant strains. This demonstrated that there is an important metabolic function unrelated to nitrogen fixation that is normally carried out by either flavodoxin or ferredoxin. If either one of these proteins is missing, the other can substitute for it. The double mutant phenotype can now be used to screen site-directed mutant versions of ferredoxin I for functionality in vivo even though the specific function of ferredoxin I is still unknown. The double mutant grew at the same slow rate under N2-fixing conditions. Thus, A. vinelandii continues to fix N2 even when both flavodoxin and ferredoxin I are missing, which suggests that a third as yet unidentified protein also serves as an electron donor to nitrogenase.
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Affiliation(s)
- A E Martin
- Department of Molecular Biology and Biochemistry, University of California, Irvine 92717
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Lankhorst RM, Katinakis P, van Kammen A, van den Bos RC. Identification and Characterization of a Bacteroid-Specific Dehydrogenase Complex in
Rhizobium leguminosarum
PRE. Appl Environ Microbiol 1988; 54:3008-13. [PMID: 16347793 PMCID: PMC204419 DOI: 10.1128/aem.54.12.3008-3013.1988] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In membranes of
Rhizobium leguminosarum
bacteroids isolated from nitrogen-fixing pea root nodules, two different protein complexes with NADH dehydrogenase activity were detected. One of these complexes, with a molecular mass of 110 kilodaltons, was also found in membranes of free-living rhizobia, but the other, with a molecular mass of 550 kilodaltons, appeared to be present only in bacteroids. The bacteroid-specific complex, referred to as DH1, probably consists of at least four different subunits. Using antibodies raised against the separate polypeptides, we found that a 35,000-molecular-weight polypeptide (35K polypeptide) in the DH1 complex is bacteroid specific, while the other proposed subunits were also detectable in cytoplasmic membranes of free-living bacteria. Dehydrogenase complex DH1 is also present in bacteroids of a
R. leguminosarum nifA
mutant, indicating that the synthesis of the dehydrogenase is not dependent on the gene product of this
nif
-regulatory gene. A possible involvement of the bacteroid-specific DH1 complex in electron transport to nitrogenase is discussed.
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Affiliation(s)
- R M Lankhorst
- Department of Molecular Biology, Agricultural University, DreijenLaan 3, 6703 HA Wageningen, The Netherlands
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Thorneley RN, Deistung J. Electron-transfer studies involving flavodoxin and a natural redox partner, the iron protein of nitrogenase. Conformational constraints on protein-protein interactions and the kinetics of electron transfer within the protein complex. Biochem J 1988; 253:587-95. [PMID: 3140782 PMCID: PMC1149338 DOI: 10.1042/bj2530587] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The kinetics of electron-transfer reactions involving flavodoxins from Klebsiella pneumoniae (KpFld), Azotobacter chroococcum (AcFld), Anacystis nidulans (AnFld) and Megasphaera elsdenii (MeFld), the free, MgADP-bound and MgATP-bound forms of the Fe protein component of nitrogenase from K. pneumoniae [Kp2, Kp2(MgADP)2 and Kp2(MgATP)2] and Na2S2O4 were studied by stopped-flow spectrophotometry. Kinetic evidence was obtained for the formation of binary protein complexes involving KpFldSQ (semiquinone) with either Kp2(MgADP)2 (KD = 49 microM) or Kp2(MgATP)2 (KD = 13 microM) but not with Kp2 (KD greater than 730 microM). The binding of 2MgATP or 2MgADP to Kp2 therefore not only shifts the midpoint potential (Em) of the [4Fe-4S] centre from -200 mV to -320 mV or -350 mV respectively but also changes the affinity of Kp2 for KpFldSQ. Thermodynamically unfavourable electron from Kp2(MgADP)2 and Kp2(MgATP)2 to KpFldSQ occurs within the protein complexes with k = 1.2 s-1 (delta E = -72 mV) and 0.5 s-1 (delta E = -120 mV) respectively. Although AcFldSQ is reduced by Kp2, Kp2(MgADP)2 and Kp2(MgATP)2 (k = 8 x 10(3), 2.4 x 10(3) and 9 x 10(2) M-1.s-1 respectively), protein-complex formation is weak in each case (KD greater than 700 microM). Electron transfer in the physiologically important and thermodynamically favourable direction from Kp2FldHQ (hydroquinone) and AcFldHQ to Kp2ox.(MgADP)2 (the state of Kp2 that accepts electrons from FldHQ in the catalytic cycle of nitrogenase) is rapid (k greater than 10(6) M-1.s-1). The second-order rate constants for the reduction of KpFldSQ, AcFldSQ, AnFldSQ and MeFldSQ by SO2.- (active reductant formed by the predissociation of S2O4(2-) ion) exhibited the linear free-energy relationship predicted by the Marcus theory of electron transfer.
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Affiliation(s)
- R N Thorneley
- A.F.R.C.-I.P.S.R., Nitrogen Fixation Laboratory, University of Sussex, Brighton, U.K
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Häger KP, Bothe H. Reduction of NAD+ by the reversed respiratory electron flow in Azotobacter vinelandii. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1987. [DOI: 10.1016/0005-2728(87)90177-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Deistung J, Thorneley RN. Electron transfer to nitrogenase. Characterization of flavodoxin from Azotobacter chroococcum and comparison of its redox potentials with those of flavodoxins from Azotobacter vinelandii and Klebsiella pneumoniae (nifF-gene product). Biochem J 1986; 239:69-75. [PMID: 3541922 PMCID: PMC1147240 DOI: 10.1042/bj2390069] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Flavodoxin in the hydroquinone state acts as an electron donor to nitrogenase in several nitrogen-fixing organisms. The mid-point potentials for the oxidized-semiquinone and semiquinone-hydroquinone couples of flavodoxins isolated from facultative anaerobe Klebsiella pneumoniae (nifF-gene product, KpFld) and the obligate aerobe Azotobacter chroococcum (AcFld) were determined as a function of pH. The mid-point potentials of the semiquinone-hydroquinone couples of KpFld and AcFld are essentially independent of pH over the range pH 7-9, being -422 mV and -522 mV (normal hydrogen electrode) at pH 7.5 respectively. The mid-point potentials of the quinone-semiquinone couples at pH 7.5 are -200 mV (KpFld) and -133 mV (AcFld) with delta Em/pH of -65 +/- 4 mV (KpFld) and -55 +/- 2 mV (AcFld) over the range pH 7.0-9.5. This indicates that reduction of the quinone is coupled to protonation to yield a neutral semiquinone. The significance of these values with respect to electron transport to nitrogenase is discussed. The amino acid compositions, the N- and C-terminal amino acid sequences and the u.v.-visible spectra of KpFld and AcFld were determined and are compared with published data for flavodoxins isolated from Azotobacter vinelandii.
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Klugkist J, Voorberg J, Haaker H, Veeger C. Characterization of three different flavodoxins from Azotobacter vinelandii. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 155:33-40. [PMID: 3948879 DOI: 10.1111/j.1432-1033.1986.tb09455.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The flavodoxins from Azotobacter vinelandii cells grown N2-fixing and from cells grown on NH4OAc have been purified and characterized. The purified flavodoxins from these cells are a mixture of three different flavodoxins (Fld I, II, III) with different primary structures. The three proteins were separated by fast protein liquid chromatography; Fld I eluted at 0.38 M KCl, Fld II at 0.43 M KCl and Fld III at 0.45 M KCl. The most striking difference between the three flavodoxins was the midpoint potential (pH 7.0, 25 degrees C) of the semiquinone/hydroquinone couple, which was -320 mV for Fld I and -500 mV for the other two flavodoxins (Fld II and Fld III). All three flavodoxins were present in cells grown on NH4OAc. In cells grown on N2 as N source only Fld I and Fld II were found. The concentration of Fld II was 10-fold higher in N2-fixing cells than in cells grown on NH4OAc. Evidence has been obtained that Fld II is involved in electron transport to nitrogenase. As will be discussed, our observation that preparations of Azotobacter flavodoxin are heterogeneous, has consequences for the published data.
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21
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Klugkist J, Haaker H, Veeger C. Studies on the mechanism of electron transport to nitrogenase in Azotobacter vinelandii. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 155:41-6. [PMID: 3456304 DOI: 10.1111/j.1432-1033.1986.tb09456.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The involvement of the cytoplasmic membrane in electron transport to nitrogenase has been studied. Evidence shows that nitrogenase activity in Azotobacter vinelandii is coupled to the flux of electrons through the respiratory chain. To obtain information about proteins involved, the changes occurring in A. vinelandii cells transferred to nitrogen-free medium after growth on NH4Cl (depression of nitrogenase activity) were studied. Synthesis of the nitrogenase polypeptides was detectable 5 min after transfer to nitrogen-free medium. No nitrogenase activity could be detected until t = 20 min, whereupon a linear increase of nitrogenase activity with time was observed. Synthesis of nitrogenase was accompanied by synthesis of flavodoxin II and two membrane-bound polypeptides of Mr 29,000 and 30,000. Analysis with respect to changes in membrane-bound NAD(P)H dehydrogenase activities revealed the induction of an NADPH dehydrogenase activity, which was not detectable in membranes isolated from cells grown in the presence of NH4OAc. This induced activity was associated with the appearance of a polypeptide of Mr 29,000 in the NADPH dehydrogenase complex.
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Hofstetter W, DerVartanian DV. A modified flavodoxin with altered redox potentials is less efficient in electron transfer to nitrogenase. Biochem Biophys Res Commun 1985; 128:643-9. [PMID: 3857914 DOI: 10.1016/0006-291x(85)90094-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The flavodoxins of the Azotobacter vinelandii wild-type and a mutant strain TZN 200 have been studied. Although the primary structure of the two proteins is the same, the ability of the mutant flavodoxin to donate electrons to nitrogenase is reduced by 75%. One reason may be the raised mid-point potential of -435 mV for the semiquinone/hydroquinone couple in the mutant flavodoxin. The respective redox potential for the wild-type flavodoxin was found to be -480 mV. As shown by paper chromatography and light absorption spectroscopy, the structure of FMN is modified in the TZN 200 flavodoxin.
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Gutschick VP. Energetics of microbial fixation of dinitrogen. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 1982. [DOI: 10.1007/3-540-11019-4_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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Carter K, Rawlings J, Orme-Johnson W, Becker R, Evans H. Purification and characterization of a ferredoxin from Rhizobium japonicum bacteroids. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85654-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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An Evaluation of N2 Fixation and H2 Production in Fermentation Culture. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/b978-0-12-040304-2.50017-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Yates MG, O'Donnell MJ, Lowe DJ, Bothe H. Ferredoxins from nitrogen-fixing bacteria. Physical and chemical characterisation of two ferredoxins from Mycobacterium flavum 301. EUROPEAN JOURNAL OF BIOCHEMISTRY 1978; 85:291-9. [PMID: 205419 DOI: 10.1111/j.1432-1033.1978.tb12238.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Scherings G, Haaker H, Veeger C. Regulation of nitrogen fixation by Fe-S protein II in Azotobacter vinelandii. EUROPEAN JOURNAL OF BIOCHEMISTRY 1977; 77:21-30. [PMID: 196854 DOI: 10.1111/j.1432-1033.1977.tb11706.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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30
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Haaker H, Veeger C. Involvement of the cytoplasmic membrane in nitrogen fixation by Azotobacter vinelandii. EUROPEAN JOURNAL OF BIOCHEMISTRY 1977; 77:1-10. [PMID: 908330 DOI: 10.1111/j.1432-1033.1977.tb11634.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Haaker H, de Kok A, Veeger C. Regulation of dinitrogen fixation in intact Azotobacter vinelandii. BIOCHIMICA ET BIOPHYSICA ACTA 1974; 357:344-57. [PMID: 4153464 DOI: 10.1016/0005-2728(74)90024-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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33
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The iron-sulphur proteins: Evolution of a ubiquitous protein from model systems to higher organisms. ACTA ACUST UNITED AC 1974. [DOI: 10.1007/bf01207637] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yates M, Jones C. Respiration and Nitrogen Fixation in Azotobacter. Adv Microb Physiol 1974. [DOI: 10.1016/s0065-2911(08)60270-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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35
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Ida S, Mori E, Morita Y. Purification, stabilization and characterization of nitrite reductase from barley roots. PLANTA 1974; 121:213-224. [PMID: 24442801 DOI: 10.1007/bf00389322] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/1974] [Indexed: 06/03/2023]
Abstract
Nitrite reductase (NiR) isolated from barley (Hordeum vulgare L.) roots was stabilized in a buffer solution containing a sulfhydryl-reducing reagent and glycerol. The enzyme was purified 340fold by ammonium sulfate fractionation and chromatography on DEAE-Sephadex A-50, Sephadex G-200 and DEAE-cellulose. Purified NiR had a specific activity of 28 μmol NO2 (-) reduced min(-1) mg(-1) of protein. The purified preparation was reddishbrown having absorption maxima at 282, 388 and 577 nm. The barley-root enzyme was almost identical with spinach-leaf NiR with respect to molecular weight, isoelectric point, pH stability, pH optimum, affinity for substrate, behavior toward inhibitors. It is concluded that NiR is the same enzymatic entity regardless of its localization in photosynthetic or nonchlorophyllous tissues. The electron-transport system for NiR in root tissue is discussed in comparison with that in leaf tissue.
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Affiliation(s)
- S Ida
- Research Institute for Food Science, Kyoto University, 611, Uji, Kyoto, Japan
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Stouthamer AH. A theoretical study on the amount of ATP required for synthesis of microbial cell material. Antonie Van Leeuwenhoek 1973; 39:545-65. [PMID: 4148026 DOI: 10.1007/bf02578899] [Citation(s) in RCA: 353] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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37
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Yoch DC. Purification and characterization of ferredoxin-nicotinamide adenine dinucleotide phosphate reductase from a nitrogen-fixing bacterium. J Bacteriol 1973; 116:384-91. [PMID: 4147648 PMCID: PMC246434 DOI: 10.1128/jb.116.1.384-391.1973] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Evidence suggesting that Bacillus polymyxa has an active ferredoxin-NADP(+) reductase (EC 1.6.99.4) was obtained when NADPH was found to provide reducing power for the nitrogenase of this organism; direct evidence was provided when it was shown that B. polymyxa extracts could substitute for the native ferredoxin-NADP(+) reductase in the photochemical reduction of NADP(+) by blue-green algal particles. The ferredoxin-NADP(+) reductase was purified about 80-fold by a combination of high-speed centrifugation, ammonium sulfate fractionation, and chromatography on Sephadex G-100 and diethylaminoethyl-cellulose. The molecular weight was estimated by gel filtration to be 60,000. A small amount of the enzyme was further purified by polyacrylamide gel electrophoresis and shown to be a flavoprotein. The reductase was specific for NADPH in the ferredoxin-dependent reduction of cytochrome c and methyl viologen diaphorase reactions; furthermore, NADP(+) was the acceptor of preference when the electron donor was photoreduced ferredoxin. The reductase also has an irreversible NADPH-NAD(+) transhydrogenase (reduced-NADP:NAD oxidoreductase, EC 1.6.1.1) activity, the rate of which was proportional to the concentration of NAD (K(m) = 5.0 x 10(-3)M). The reductase catalyzed electron transfer from NADPH not only to B. polymyxa ferredoxin but also to the ferredoxins of Clostridium pasteurianum, Azotobacter vinelandii, and spinach chloroplasts, although less effectively. Rubredoxin from Clostridium acidi-urici and azotoflavin from A. vinelandii also accept electrons from the B. polymyxa reductase. The pH optima for the various reactions catalyzed by the B. polymyxa ferredoxin-NADP reductase are similar to those of the chloroplast reductase. NAD and acetyl-coenzyme A, which obligatorily activate NADPH- and NADH-ferredoxin reductases, respectively, in Clostridium kluyveri, have no effect on B. polymyxa reductase.
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Jungermann K, Thauer RK, Leimenstoll G, Decker K. Function of reduced pyridine nucleotide-ferredoxin oxidoreductases in saccharolytic Clostridia. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 305:268-80. [PMID: 4147457 DOI: 10.1016/0005-2728(73)90175-8] [Citation(s) in RCA: 146] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Yoch DC. The electron transport system in nitrogen fixation by azotobacter. IV. Some oxidation-reduction properties of azotoflavin. Biochem Biophys Res Commun 1972; 49:335-42. [PMID: 4404816 DOI: 10.1016/0006-291x(72)90415-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Yates MG. Electron transport to nitrogenase in Azotobacter chroococcum: Azotobacter flavodoxin hydroquinone as an electron donor. FEBS Lett 1972; 27:63-67. [PMID: 11946808 DOI: 10.1016/0014-5793(72)80410-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- M G. Yates
- A.R.C. Unit of Nitrogen Fixation, University of Sussex, Brighton, BN1 9QJ, Sussex, UK
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42
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Yoch DC, Arnon DI. Two Biologically Active Ferredoxins from the Aerobic Nitrogen-fixing Bacterium, Azotobacter vinelandii. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(19)45017-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Haaker H, Bresters TW, Veeger C. Relation between anaerobic ATP synthesis from pyruvate and nitrogen fixation in Azotobacter vinelandii. FEBS Lett 1972; 23:160-2. [PMID: 4343927 DOI: 10.1016/0014-5793(72)80330-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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44
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Van Lin B, Bothe H. Flavodoxin from Azotobacter vinelandii. ARCHIV FUR MIKROBIOLOGIE 1972; 82:155-72. [PMID: 4401956 DOI: 10.1007/bf01890407] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Ackrell BA, Erickson SK, Jones CW. The respiratory-chain NADPH dehydrogenase of Azotobacter vinelandii. EUROPEAN JOURNAL OF BIOCHEMISTRY 1972; 26:387-92. [PMID: 4402559 DOI: 10.1111/j.1432-1033.1972.tb01778.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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46
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Ackrell BA, Erickson SK, Jones CW. The allosteric properties of the reduced nicotinamide-adenine dinucleotide phosphate dehydrogenase of Azotobacter vinelandii respiratory membranes. Biochem J 1972; 127:75P. [PMID: 4403930 PMCID: PMC1178745 DOI: 10.1042/bj1270075pa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Yates MG. Electron transport to nitrogenase in Azotobacter chroococcum. Purification and some properties of NADH dehydrogenase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1971; 24:347-57. [PMID: 4400495 DOI: 10.1111/j.1432-1033.1971.tb19693.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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49
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Benemann JR, Sheu CW, Valentine RC. Temperature sensitive nitrogen fixation mutants of Azotobacter vinelandii. ARCHIV FUR MIKROBIOLOGIE 1971; 79:49-58. [PMID: 5110121 DOI: 10.1007/bf00412040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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