To Which Substance Does Ferredoxin Transfer an Electron

To Which Substance Does Ferredoxin Transfer an Electron

ferredoxin-NADP+ reductase
Identifiers
EC no. 1.18.one.2
CAS no. 9029-33-eight
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM contour
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO

In enzymology, a
ferredoxin-NADP+
reductase

(EC 1.xviii.i.2) abbreviated
FNR, is an enzyme that catalyzes the chemical reaction

2 reduced ferredoxin + NADP+
+ H+









{\displaystyle \rightleftharpoons }




2 oxidized ferredoxin + NADPH

The 3 substrates of this enzyme are reduced ferredoxin, NADP+, and H+, whereas its 2 products are oxidized ferredoxin and NADPH. Information technology has a flavin cofactor, FAD.

This enzyme belongs to the family unit of oxidoreductases, that use iron-sulfur proteins equally electron donors and NAD+
or NADP+
every bit electron acceptors.

This enzyme participates in photosynthesis. FNR provides a major source of NADPH for photosynthetic organisms.[1]

Classification

[edit]

The systematic proper noun of this enzyme class is ferredoxin:NADP+
oxidoreductase. Other names in common employ include:

  • adrenodoxin reductase,
  • ferredoxin-NADP+
    reductase,
  • ferredoxin-NADP+
    oxidoreductase,
  • ferredoxin-nicotinamide adenine dinucleotide phosphate reductase,
  • ferredoxin-nicotinamide-adenine dinucleotide phosphate (oxidized), reductase
  • ferredoxin-TPN reductase,
  • NADP+:ferredoxin oxidoreductase,
  • NADPH:ferredoxin oxidoreductase,
  • reduced nicotinamide adenine dinucleotide phosphate-adrenodoxin, reductase, and
  • TPNH-ferredoxin reductase

Mechanism

[edit]

Cartoon depicting ferredoxin transferring an electron to FNR.

Cartoon depicting FAD (crimson) and NADP+
(bluish) jump in the agile site of the enzyme. Reduced ferredoxin binds the enzyme and transfers one electron to FAD. (image from PDB file 2BSA)

During photosynthesis, electrons are removed from water and transferred to the unmarried electron carrier ferredoxin. Ferredoxin: NADP+
reductase and so transfers an electron from each of two ferredoxin molecules to a unmarried molecule of the 2 electron carrier NADPH.[two]
FNR utilizes FAD, which can be in an oxidized state, single electron reduced semiquinone country, and fully reduced state to mediate this electron transfer.[3]

FNR has an induced-fit mechanism of catalysis.[iii]
Bounden of ferredoxin to the enzyme causes the germination of a hydrogen bond between a glutamate residue (E312) and a serine residue (S96) in the active site.[4]
The glutamate residue is highly conserved considering it both stabilizes the semiquinone form of FAD and is a proton donor/acceptor in the reaction.[v]
The rate limiting step of the electron transfer reaction is the release of the first oxidized ferredoxin molecule after the reduction of FAD with 1 electron.[3]
This step is inhibited by the presence of oxidized ferredoxin and stimulated by the presence of NADP+.[3]
The binding of NADP+
to the enzyme lowers the binding affinity of the enzyme for ferredoxin.[6]

This reaction can besides operate in reverse to generate reduced ferredoxin, which can then be used in a variety of biosynthetic pathways. Some bacteria and algae utilize the molecule flavodoxin instead of ferredoxin equally the single electron carrier molecule to be reduced or oxidized.[3]

Structure

[edit]

FNR crystal structure.

FNR construction with beta butt domain colored yellow, blastoff helix-beta sheet fold colored green, and FAD cofactor colored reddish. (paradigm from PDB file 3LVB)

Plant-type ferredoxin: NADP+
reductase has two structural domains. The first domain is an antiparallel beta barrel at the amino terminus of the protein that contains the bounden domain for the FAD cofactor.[vii]
The second domain is at the carboxyl terminus of the poly peptide and contains an blastoff helix-beta strand fold.[7]
This terminal domain is where the NADP+
binds.[8]
The active site for the enzyme occurs at the interface between the ii domains.[9]

Binding of the enzyme to the thylakoid membrane involves a polyproline type Two helix created between 2 FNR monomers and several proline rich integral membrane proteins.[x]

As of late 2007, 54 structures had been solved for this class of enzymes, with PDB accession codes 1B2R, 1BJK, 1BQE, 1BX0, 1BX1, 1CJC, 1E1L, 1E62, 1E63, 1E64, 1E6E, 1EWY, 1FDR, 1FNB, 1FNC, 1FND, 1FRN, 1FRQ, 1GAQ, 1GAW, 1GJR, 1GO2, 1GR1, 1H42, 1H85, 1JB9, 1OGI, 1OGJ, 1QFY, 1QFZ, 1QG0, 1QGA, 1QGY, 1QGZ, 1QH0, 1QUE, 1QUF, 1SM4, 1W34, 1W35, 1W87, 2B5O, 2BGI, 2BGJ, 2BMW, 2BSA, 2C7G, 2GQW, 2GR0, 2GR1, 2GR2, 2GR3, 2OK7, and 2OK8.

Part

[edit]

Ferredoxin: NADP+
reductase is the last enzyme in the transfer of electrons during photosynthesis from photosystem I to NADPH.[2]
The NADPH is then used every bit a reducing equivalent in the reactions of the Calvin cycle.[2]
Electron cycling from ferredoxin to NADPH only occurs in the light in part because FNR activity is inhibited in the dark.[11]
In nonphotosynthetic organisms, the FNR primarily works in reverse to provide reduced ferredoxin for various metabolic pathways. These pathways include nitrogen fixation, terpenoid biosynthesis, steroid metabolism, oxidative stress response, and iron–sulfur protein biogenesis.[seven]

FNR is a soluble protein that is found both complimentary in the chloroplast stroma and bound to the thylakoid membrane. This binding occurs opposite to the agile site of the enzyme and does not seem to bear on the construction of the active site or have a significant impact on the enzyme’s activeness.[10]
When bound to the thylakoid membrane, the enzyme exists as a dimer, but when it is free in the stroma, it is monomeric.[10]
The binding of the FNR to the integral membrane proteins on the thylakoid membrane is enhanced under acidic conditions, so recruitment and binding of FNR to the thylakoid membrane may be a method of storing and stabilizing the enzyme in the dark when photosynthesis is not occurring.[12]
The chloroplast stroma varies from being slightly acidic in the dark to more than alkaline metal in the light.[ten]
Therefore, in the dark, more than FNRs would be recruited and leap to the thylakoid membrane, and in the calorie-free, more FNRs would dissociate from the membrane and exist costless in the stroma.

Development

[edit]

Ferredoxin NADP+
reductases are nowadays in many organisms, including plants, bacteria, and the mitochondria of eukaryotes. Yet, these proteins belong to two unrelated protein families and are an example of convergent development.[vii]
[13]
The plant-blazon FNRs (InterPro:IPR015701, InterPro:IPR033892) include the plastidic FNRs seen in plants.[7]
[13]
The glutathione-reductase-blazon FNRs (InterPro:IPR022890, InterPro:IPR021163), sometimes named adrenodoxin-NADP+ reductase for stardom, are seen in the mitochondria of eukaryotes.[vii]
[thirteen]
Both families are seen in bacteria. Two actress families, i thioredoxin reductase-like (TRLF) and the other with a unique mechanism (NfnAB), has been identified.[14]

In the establish-similar family unit of FNRs, selective evolutionary force per unit area has led to differences in the catalytic efficiency of FNRs in photosynthetic and nonphotosynthetic organisms. Electron transfer by FNR is a rate limiting footstep in photosynthesis, and so the plastidic FNR in plants have evolved to exist highly efficient.[viii]
These plastidic FNRs are xx–100 fold more agile than bacterial FNRs.[xv]
This higher catalytic efficiency of the transfer of electrons from FAD to NADP+
is related to structural changes in the active site that reduce the distance between the N5 in FAD and the C4 in NADP+.[16]
The plastidic FNRs in plants have besides evolved to accept a high degree of substrate specificity for NADP+
over NAD+; studies of amino acid mutations have shown that the final tyrosine remainder in plastidic FNRs plays a fundamental role in this substrate specificity.[8]
In contrast, some nonphotosynthetic FNRs exercise not preferentially bind NADP+
and lack this tyrosine residue.[16]

Affliction relevance

[edit]

Several major human being diseases are caused by the obligate intracellular protozoan parasites in the phylum Apicomplexa. The apicoplast organelle in these organisms is believed to have come from an endosymbiotic event in which an ancestral protozoan engulfed an algal cell.[7]
These apicoplasts contain plant-like FNRs that the protozoan uses to generate reduced ferredoxin, which is so used as a reductant in essential biosynthetic pathways.[17]
FNRs from two major parasites affecting humans,
Plasmodium falciparum, which causes malaria, and
Toxoplasma gondii, which causes toxoplasmosis, have been sequenced.[18]
Since humans do not have a homologous protein, these enzymes are possible new targets for drug therapies confronting these diseases.[18]

References

[edit]


  1. ^


    Spaans SK, Weusthuis RA, van der Oost J, Kengen SW (2015-07-29). “NADPH-generating systems in bacteria and archaea”.
    Frontiers in Microbiology.
    half dozen: 742. doi:10.3389/fmicb.2015.00742. PMC4518329. PMID 26284036.


  2. ^


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    Berg JM, Tymoczko JL, Stryer L (2007).
    Biochemistry
    (6th ed.). New York: W.H. Freeman. ISBN978-0-7167-8724-2.


  3. ^


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    Carrillo North, Ceccarelli EA (May 2003). “Open questions in ferredoxin-NADP+ reductase catalytic mechanism”.
    European Periodical of Biochemistry.
    270
    (9): 1900–xv. doi:10.1046/j.1432-1033.2003.03566.10. PMID 12709048.



  4. ^


    Kurisu G, Kusunoki K, Katoh East, Yamazaki T, Teshima K, Onda Y, et al. (February 2001). “Structure of the electron transfer circuitous between ferredoxin and ferredoxin-NADP(+) reductase”.
    Nature Structural Biology.
    eight
    (2): 117–21. doi:x.1038/84097. PMID 11175898. S2CID 13611907.



  5. ^


    Dumit Vi, Essigke T, Cortez N, Ullmann GM (April 2010). “Mechanistic insights into ferredoxin-NADP(H) reductase catalysis involving the conserved glutamate in the active site”.
    Journal of Molecular Biology.
    397
    (3): 814–25. doi:10.1016/j.jmb.2010.01.063. PMID 20132825.



  6. ^


    Medina Thousand (Baronial 2009). “Structural and mechanistic aspects of flavoproteins: photosynthetic electron transfer from photosystem I to NADP+”.
    The FEBS Journal.
    276
    (15): 3942–58. doi:x.1111/j.1742-4658.2009.07122.ten. PMID 19583765. S2CID 42610724.


  7. ^


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    d




    e




    f




    thousand




    Aliverti A, Pandini V, Pennati A, de Rosa M, Zanetti G (June 2008). “Structural and functional diversity of ferredoxin-NADP(+) reductases”.
    Archives of Biochemistry and Biophysics.
    474
    (2): 283–91. doi:10.1016/j.abb.2008.02.014. hdl:2434/41439. PMID 18307973.


  8. ^


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    Paladini DH, Musumeci MA, Carrillo North, Ceccarelli EA (June 2009). “Induced fit and equilibrium dynamics for high catalytic efficiency in ferredoxin-NADP(H) reductases”.
    Biochemistry.
    48
    (24): 5760–8. doi:x.1021/bi9004232. PMID 19435322.



  9. ^


    Arakaki AK, Ceccarelli EA, Carrillo N (February 1997). “Plant-type ferredoxin-NADP+ reductases: a basal structural framework and a multiplicity of functions”.
    FASEB Journal.
    xi
    (2): 133–40. doi:10.1096/fasebj.11.2.9039955. PMID 9039955. S2CID 99698.


  10. ^


    a




    b




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    d




    Alte F, Stengel A, Benz JP, Petersen E, Soll J, Groll G, Bölter B (November 2010). “Ferredoxin:NADPH oxidoreductase is recruited to thylakoids by binding to a polyproline type II helix in a pH-dependent way”.
    Proceedings of the National University of Sciences of the Usa.
    107
    (45): 19260–5. Bibcode:2010PNAS..10719260A. doi:10.1073/pnas.1009124107. PMC2984204. PMID 20974920.



  11. ^


    Talts Due east, Oja Five, Rämma H, Rasulov B, Anijalg A, Laisk A (Oct 2007). “Dark inactivation of ferredoxin-NADP reductase and cyclic electron flow under far-reddish low-cal in sunflower leaves”.
    Photosynthesis Research.
    94
    (1): 109–xx. doi:10.1007/s11120-007-9224-vii. PMID 17665150. S2CID 416310.



  12. ^


    Benz JP, Lintala M, Soll J, Mulo P, Bölter B (Nov 2010). “A new concept for ferredoxin-NADP(H) oxidoreductase binding to plant thylakoids”.
    Trends in Plant Science.
    15
    (11): 608–13. doi:10.1016/j.tplants.2010.08.008. PMID 20851663.


  13. ^


    a




    b




    c




    Pierella Karlusich JJ, Carrillo N (Dec 2017). “Evolution of the acceptor side of photosystem I: ferredoxin, flavodoxin, and ferredoxin-NADP+
    oxidoreductase”.
    Photosynthesis Research.
    134
    (3): 235–250. doi:10.1007/s11120-017-0338-2. PMID 28150152. S2CID 9223061.



  14. ^


    Spaans SK, Weusthuis RA, van der Oost J, Kengen SW (2015). “NADPH-generating systems in bacteria and archaea”.
    Frontiers in Microbiology.
    half dozen: 742. doi:10.3389/fmicb.2015.00742. PMC4518329. PMID 26284036.



  15. ^


    Orellano EG, Calcaterra NB, Carrillo N, Ceccarelli EA (September 1993). “Probing the role of the carboxyl-last region of ferredoxin-NADP+ reductase by site-directed mutagenesis and deletion assay”.
    The Journal of Biological Chemical science.
    268
    (26): 19267–73. doi:10.1016/S0021-9258(19)36509-iii. PMID 8366077.


  16. ^


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    Peregrina JR, Sánchez-Azqueta A, Herguedas B, Martínez-Júlvez One thousand, Medina M (September 2010). “Role of specific residues in coenzyme binding, accuse-transfer complex germination, and catalysis in Anabaena ferredoxin NADP+-reductase”.
    Biochimica et Biophysica Acta (BBA) – Bioenergetics.
    1797
    (ix): 1638–46. doi:10.1016/j.bbabio.2010.05.006. PMID 20471952.



  17. ^


    Balconi E, Pennati A, Crobu D, Pandini V, Cerutti R, Zanetti G, Aliverti A (July 2009). “The ferredoxin-NADP+ reductase/ferredoxin electron transfer system of Plasmodium falciparum”.
    The FEBS Journal.
    276
    (14): 3825–36. doi:10.1111/j.1742-4658.2009.07100.ten. PMID 19523113. S2CID 24183752.


  18. ^


    a




    b




    Seeber F, Aliverti A, Zanetti 1000 (2005). “The found-type ferredoxin-NADP+ reductase/ferredoxin redox organization as a possible drug target against apicomplexan human parasites”.
    Current Pharmaceutical Pattern.
    eleven
    (24): 3159–72. doi:10.2174/1381612054864957. PMID 16178751.


Further reading

[edit]

  • Omura T, Sanders E, Estabrook RW, Cooper DY, Rosenthal O (1966). “Isolation from adrenal cortex of a nonheme atomic number 26 protein and a flavoprotein functional as a reduced triphosphopyridine nucleotide-cytochrome P-450 reductase”.
    Arch. Biochem. Biophys.
    117
    (iii): 660–673. doi:10.1016/0003-9861(66)90108-ane.

  • Shin Chiliad, Tagawa Grand, Arnon DI (1963). “Crystallization of ferredoxin-TPN reductase and its office in the photosynthetic apparatus of chloroplasts”.
    Biochemische Zeitschrift.
    338: 84–96. PMID 14087348.

External links

[edit]


  • Media related to Ferredoxin—NADP(+) reductase at Wikimedia Commons



To Which Substance Does Ferredoxin Transfer an Electron

Source: https://en.wikipedia.org/wiki/Ferredoxin%E2%80%94NADP(%2B)_reductase

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