Publications by authors named "Maria S Fadeeva"

4 Publications

  • Page 1 of 1

Alternative pyrimidine biosynthesis protein ApbE is a flavin transferase catalyzing covalent attachment of FMN to a threonine residue in bacterial flavoproteins.

J Biol Chem 2013 May 4;288(20):14276-14286. Epub 2013 Apr 4.

Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119992, Russia. Electronic address:

Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) contains two flavin residues as redox-active prosthetic groups attached by a phosphoester bond to threonine residues in subunits NqrB and NqrC. We demonstrate here that flavinylation of truncated Vibrio harveyi NqrC at Thr-229 in Escherichia coli cells requires the presence of a co-expressed Vibrio apbE gene. The apbE genes cluster with genes for Na(+)-NQR and other FMN-binding flavoproteins in bacterial genomes and encode proteins with previously unknown function. Experiments with isolated NqrC and ApbE proteins confirmed that ApbE is the only protein factor required for NqrC flavinylation and also indicated that the reaction is Mg(2+)-dependent and proceeds with FAD but not FMN. Inactivation of the apbE gene in Klebsiella pneumoniae, wherein the nqr operon and apbE are well separated in the chromosome, resulted in a complete loss of the quinone reductase activity of Na(+)-NQR, consistent with its dependence on covalently bound flavin. Our data thus identify ApbE as a novel modifying enzyme, flavin transferase.
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http://dx.doi.org/10.1074/jbc.M113.455402DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3656284PMC
May 2013

Redox properties of the prosthetic groups of Na(+)-translocating nadh:quinone oxidoreductase. 1. Electron paramagnetic resonance study of the enzyme.

Biochemistry 2009 Jul;48(27):6291-8

Department of Molecular Energetics of Microorganisms, A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia.

Redox properties of all EPR-detectable prosthetic groups of Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) from Vibrio harveyi were studied at pH 7.5 using cryo-EPR spectroelectrochemistry. Titration shows five redox transitions. One with E(m) = -275 mV belongs to the reduction of the [2Fe-2S] cluster, and the four others reflect redox transitions of flavin cofactors. Two transitions (E(m)(1) = -190 mV and E(m)(2) = -275 mV) originate from the formation of FMN anion radical, covalently bound to the NqrC subunit, and its subsequent reduction. The remaining two transitions arise from the two other flavin cofactors. A high potential (E(m) = -10 mV) transition corresponds to the reduction of riboflavin neutral radical, which is stable at rather high redox potentials. An E(m) = -130 mV transition reflects the formation of FMN anion radical from a flavin covalently bound to the NqrB subunit, which stays as a radical down to very low potentials. Taking into account the EPR-silent, two-electron transition of noncovalently bound FAD located in the NqrF subunit, there are four flavins in Na(+)-NQR all together. Defined by dipole-dipole magnetic interaction measurements, the interspin distance between the [2Fe-2S](+) cluster and the NqrB subunit-bound FMN anion radical is found to be 22.5 +/- 1.5 A, which means that for the functional electron transfer between these two centers another cofactor, most likely FMN bound to the NqrC subunit, should be located.
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http://dx.doi.org/10.1021/bi900524mDOI Listing
July 2009

Catalytic properties of Na+-translocating NADH:quinone oxidoreductases from Vibrio harveyi, Klebsiella pneumoniae, and Azotobacter vinelandii.

FEMS Microbiol Lett 2008 Feb;279(1):116-23

Department of Molecular Energetics of Microorganisms, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.

The catalytic properties of sodium-translocating NADH:quinone oxidoreductases (Na+-NQRs) from the marine bacterium Vibrio harveyi, the enterobacterium Klebsiella pneumoniae, and the soil microorganism Azotobacter vinelandii have been comparatively analyzed. It is shown that these enzymes drastically differ in their affinity to sodium ions. The enzymes also possess different sensitivity to inhibitors. Na+-NQR from A. vinelandii is not sensitive to low 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO) concentrations, while Na+-NQR from K. pneumoniae is fully resistant to either Ag+ or N-ethylmaleimide. All the Na+-NQR-type enzymes are sensitive to diphenyliodonium, which is shown to modify the noncovalently bound FAD of the enzyme.
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http://dx.doi.org/10.1111/j.1574-6968.2007.01015.xDOI Listing
February 2008

Regulation of expression of Na+ -translocating NADH:quinone oxidoreductase genes in Vibrio harveyi and Klebsiella pneumoniae.

Arch Microbiol 2007 Oct 6;188(4):341-8. Epub 2007 Jun 6.

Department of Molecular Energetics of Microorganisms, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskie Gory, Moscow 119992, Russia.

The expression of genes encoding sodium-translocating NADH:quinone oxidoreductase (Na(+)-NQR) was studied in the marine bacterium Vibrio harveyi and in the enterobacterium Klebsiella pneumoniae. It has been shown that such parameters as NaCl concentration, pH value, and presence of an uncoupler in the growth media do not influence significantly the level of nqr expression. However, nqr expression depends on the growth substrates used by these bacteria. Na(+)-NQR is highly repressed in V. harveyi during anaerobic growth, and nqr expression is modulated by electron acceptors and values of their redox potentials. The latter effect was shown to be independent of the ArcAB regulatory system.
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http://dx.doi.org/10.1007/s00203-007-0254-5DOI Listing
October 2007
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