Protochlorophyllide reductase

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The reduction of ring D of protochlorophyllide completes the biosynthesis of chlorophyllide a Chlorophillide synthesis.svg
The reduction of ring D of protochlorophyllide completes the biosynthesis of chlorophyllide a
light-dependent protochlorophyllide reductase
Identifiers
EC no. 1.3.1.33
CAS no. 68518-04-7
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light-independent protochlorophyllide reductase
Dpor.png
Crystallographic structure of heterooctamer of a dark-operative protochlorophyllide oxidoreductase from Prochlorococcus marinus. [1]
Identifiers
EC no. 1.3.7.7
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Search
PMC articles
PubMed articles
NCBI proteins

In enzymology, protochlorophyllide reductases (POR) [2] [3] are enzymes that catalyze the conversion from protochlorophyllide to chlorophyllide a. They are oxidoreductases participating in the biosynthetic pathway to chlorophylls. [4] [5]

Contents

There are two structurally unrelated proteins with this sort of activity, referred to as light-dependent (LPOR) and dark-operative (DPOR). The light- and NADPH-dependent reductase is part of the short-chain dehydrogenase/reductase (SDR) superfamily and is found in plants and oxygenic photosynthetic bacteria, [6] [7] while the ATP-dependent dark-operative version is a completely different protein, consisting of three subunits that exhibit significant sequence and quaternary structure similarity to the three subunits of nitrogenase. [8] This enzyme may be evolutionary older; due to its bound iron-sulfur clusters is highly sensitive to free oxygen and does not function if the atmospheric oxygen concentration exceeds about 3%. [9] It is possible that evolutionary pressure associated with the great oxidation event resulted in the development of the light-dependent system.

The light-dependent version (EC 1.3.1.33) uses NADPH:

protochlorophyllide + NADPH + H+ chlorophyllide a + NADP+

While the light-independent or dark-operative version (EC 1.3.7.7) uses ATP and ferredoxin: [10] [11] [12]

protochlorophyllide a + reduced ferredoxin + 2 ATP + 2 H2O = chlorophyllide a + oxidized ferredoxin + 2 ADP + 2 phosphate

Light-dependent

The light-dependent version has the accepted name protochlorophyllide reductase. The systematic name is chlorophyllide-a :NADP+ 7,8-oxidoreductase. Other names in common use include NADPH2-protochlorophyllide oxidoreductase, NADPH-protochlorophyllide oxidoreductase, NADPH-protochlorophyllide reductase, protochlorophyllide oxidoreductase, and protochlorophyllide photooxidoreductase.

LPOR is one of only three known light-dependent enzymes. The enzyme enables light-dependent protochlorophyllide reduction via direct local hydride transfer from NADPH and a longer-range proton transfer along a defined structural pathway. [13] LPOR is a ~40kDa monomeric enzyme, for which the structure has been solved by X-ray crystallography. It is part of the SDR superfamily, which includes alcohol dehydrogenase, and consists of a Rossman-fold NADPH-binding site and a substrate-specific C-terminal segment region. The protochlorophyllide substrate is thought to bind to a cavity near the nicotinamide end of the bound NADPH. [7] [13] LPOR is primarily found in plants and oxygenic photosynthetic bacteria, as well as in some algae.

Light-independent

The light-independent version has the accepted name of ferredoxin:protochlorophyllide reductase (ATP-dependent). Systematically it is known as ATP-dependent ferredoxin:protochlorophyllide-a 7,8-oxidoreductase. Other names in common use include light-independent protochlorophyllide reductase and dark-operative protochlorophyllide reductase (DPOR).

DPOR is a nitrogenase homologue [8] and adopts an almost identical overall architecture arrangement to both nitrogenase as well as the downstream chlorophyllide a reductase (COR). The enzyme consists of a catalytic heterotetramer and two transiently-bound ATPase dimers (right). [14] Similar to nitrogenase, the reduction mechanism relies on an electron transfer from the iron-sulfur cluster of the ATPase domain, through a secondary cluster on the catalytic heterotetramer and finally to the protochlorophyllide-bound active site (which, distinct from nitrogenase, does not contain FeMoco). The reduction requires significantly less input than the nitrogenase reaction, requiring only a 2-electron reduction and 4 ATP equivalents, and as such may require an auto-inhibitory mechanism to avoid over-activity. [15]

DPOR can alternatively take as its substrate the compound with a second vinyl group (instead of an ethyl group) in the structure, in which case the reaction is

3,8-divinylprotochlorophyllide + reduced ferredoxin + 2 ATP + 2 H2O 3,8-divinylchlorophyllide a + oxidized ferredoxin + 2 ADP + 2 phosphate

This enzyme is present in photosynthetic bacteria, cyanobacteria, green algae and gymnosperms. [4] [16]

See also

Related Research Articles

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Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words χλωρός, khloros and φύλλον, phyllon ("leaf"). Chlorophyll allow plants to absorb energy from light.

<span class="mw-page-title-main">Nicotinamide adenine dinucleotide</span> Chemical compound which is reduced and oxidized

Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other, nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD+ and NADH (H for hydrogen), respectively.

<span class="mw-page-title-main">Nicotinamide adenine dinucleotide phosphate</span> Chemical compound

Nicotinamide adenine dinucleotide phosphate, abbreviated NADP+ or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADPH as a reducing agent ('hydrogen source'). NADPH is the reduced form of NADP+, the oxidized form. NADP+ is used by all forms of cellular life.

<span class="mw-page-title-main">Nitrogenase</span> Class of enzymes

Nitrogenases are enzymes (EC 1.18.6.1EC 1.19.6.1) that are produced by certain bacteria, such as cyanobacteria (blue-green bacteria) and rhizobacteria. These enzymes are responsible for the reduction of nitrogen (N2) to ammonia (NH3). Nitrogenases are the only family of enzymes known to catalyze this reaction, which is a step in the process of nitrogen fixation. Nitrogen fixation is required for all forms of life, with nitrogen being essential for the biosynthesis of molecules (nucleotides, amino acids) that create plants, animals and other organisms. They are encoded by the Nif genes or homologs. They are related to protochlorophyllide reductase.

<span class="mw-page-title-main">Photosystem I</span> Second protein complex in photosynthetic light reactions

Photosystem I is one of two photosystems in the photosynthetic light reactions of algae, plants, and cyanobacteria. Photosystem I is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. Ultimately, the electrons that are transferred by Photosystem I are used to produce the moderate-energy hydrogen carrier NADPH. The photon energy absorbed by Photosystem I also produces a proton-motive force that is used to generate ATP. PSI is composed of more than 110 cofactors, significantly more than Photosystem II.

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Iron–sulfur proteins are proteins characterized by the presence of iron–sulfur clusters containing sulfide-linked di-, tri-, and tetrairon centers in variable oxidation states. Iron–sulfur clusters are found in a variety of metalloproteins, such as the ferredoxins, as well as NADH dehydrogenase, hydrogenases, coenzyme Q – cytochrome c reductase, succinate – coenzyme Q reductase and nitrogenase. Iron–sulfur clusters are best known for their role in the oxidation-reduction reactions of electron transport in mitochondria and chloroplasts. Both Complex I and Complex II of oxidative phosphorylation have multiple Fe–S clusters. They have many other functions including catalysis as illustrated by aconitase, generation of radicals as illustrated by SAM-dependent enzymes, and as sulfur donors in the biosynthesis of lipoic acid and biotin. Additionally, some Fe–S proteins regulate gene expression. Fe–S proteins are vulnerable to attack by biogenic nitric oxide, forming dinitrosyl iron complexes. In most Fe–S proteins, the terminal ligands on Fe are thiolate, but exceptions exist.

<span class="mw-page-title-main">Shikimate dehydrogenase</span> Enzyme involved in amino acid biosynthesis

In enzymology, a shikimate dehydrogenase (EC 1.1.1.25) is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">Divinyl chlorophyllide a 8-vinyl-reductase</span> Class of enzymes

In enzymology, divinyl chlorophyllide a 8-vinyl-reductase (EC 1.3.1.75) is an enzyme that catalyzes the chemical reaction

In enzymology, a phycocyanobilin:ferredoxin oxidoreductase is an enzyme that catalyzes the chemical reaction

In enzymology, a phytochromobilin:ferredoxin oxidoreductase is an enzyme that catalyzes the chemical reaction

In enzymology, a ferredoxin-NADP+ reductase (EC 1.18.1.2) abbreviated FNR, is an enzyme that catalyzes the chemical reaction

In enzymology, a dephospho-[reductase kinase] kinase is an enzyme that catalyzes the chemical reaction

<span class="mw-page-title-main">Protochlorophyllide</span> Chemical compound

Protochlorophyllide, or monovinyl protochlorophyllide, is an intermediate in the biosynthesis of chlorophyll a. It lacks the phytol side-chain of chlorophyll and the reduced pyrrole in ring D. Protochlorophyllide is highly fluorescent; mutants that accumulate it glow red if irradiated with blue light. In angiosperms, the later steps which convert protochlorophyllide to chlorophyll are light-dependent, and such plants are pale (chlorotic) if grown in the darkness. Gymnosperms, algae, and photosynthetic bacteria have another, light-independent enzyme and grow green in the darkness as well.

<span class="mw-page-title-main">Light-dependent reactions</span> Photosynthetic reactions

Light-dependent reactions is jargon for certain photochemical reactions that are involved in photosynthesis, the main process by which plants acquire energy. There are two light dependent reactions, the first occurs at photosystem II (PSII) and the second occurs at photosystem I (PSI),

Chlorophyll(ide) b reductase (EC 1.1.1.294), chlorophyll b reductase, Chl b reductase) is an enzyme with systematic name 71-hydroxychlorophyllide-a:NAD(P)+ oxidoreductase. This enzyme catalyses the following chemical reaction

<span class="mw-page-title-main">Chlorophyllide-a oxygenase</span> Class of enzymes

Chlorophyllide-a oxygenase (EC 1.14.13.122), chlorophyllide a oxygenase, chlorophyll-b synthase, CAO) is an enzyme with systematic name chlorophyllide-a:oxygen 7-oxidoreductase. This enzyme catalyses the following chemical reactions

<span class="mw-page-title-main">Magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase</span> Class of enzymes

Magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase, is an enzyme with systematic name magnesium-protoporphyrin-IX 13-monomethyl ester, ferredoxin:oxygen oxidoreductase (hydroxylating). In plants this enzyme catalyses the following overall chemical reaction

<span class="mw-page-title-main">Chlorophyllide</span> Chemical compound

Chlorophyllide a and Chlorophyllide b are the biosynthetic precursors of chlorophyll a and chlorophyll b respectively. Their propionic acid groups are converted to phytyl esters by the enzyme chlorophyll synthase in the final step of the pathway. Thus the main interest in these chemical compounds has been in the study of chlorophyll biosynthesis in plants, algae and cyanobacteria. Chlorophyllide a is also an intermediate in the biosynthesis of bacteriochlorophylls.

<span class="mw-page-title-main">Chlorophyllide a reductase</span> Enzyme

Chlorophyllide a reductase (EC 1.3.7.15), also known as COR, is an enzyme with systematic name bacteriochlorophyllide-a:ferredoxin 7,8-oxidoreductase. It catalyses the following chemical reaction

References

  1. ↑ PDB: 2ynm ​; Moser J, Lange C, Krausze J, Rebelein J, Schubert WD, Ribbe MW, Heinz DW, Jahn D (2013). "Structure of ADP-aluminium fluoride-stabilized protochlorophyllide oxidoreductase complex". Proc Natl Acad Sci U S A. 110 (6): 2094–2098. Bibcode:2013PNAS..110.2094M. doi: 10.1073/pnas.1218303110 . PMC   3568340 . PMID   23341615.
  2. ↑ Griffiths WT (1978). "Reconstitution of chlorophyllide formation by isolated etioplast membranes". Biochem. J. 174 (3): 681–92. doi:10.1042/bj1740681. PMC   1185970 . PMID   31865.
  3. ↑ Apel K, Santel HJ, Redlinger TE, Falk H (1980). "The protochlorophyllide holochrome of barley (Hordeum vulgare L.) Isolation and characterization of the NADPH:protochlorophyllide oxidoreductase". Eur. J. Biochem. 111 (1): 251–8. doi: 10.1111/j.1432-1033.1980.tb06100.x . PMID   7439188.
  4. 1 2 Willows, Robert D. (2003). "Biosynthesis of chlorophylls from protoporphyrin IX". Natural Product Reports. 20 (6): 327–341. doi:10.1039/B110549N. PMID   12828371.
  5. ↑ Bollivar, David W. (2007). "Recent advances in chlorophyll biosynthesis". Photosynthesis Research. 90 (2): 173–194. doi:10.1007/s11120-006-9076-6. PMID   17370354. S2CID   23808539.
  6. ↑ Nomata, Jiro; Kondo, Toru; Mizoguchi, Tadashi; Tamiaki, Hitoshi; Itoh, Shigeru; Fujita, Yuichi (May 2015). "Dark-operative protochlorophyllide oxidoreductase generates substrate radicals by an iron-sulphur cluster in bacteriochlorophyll biosynthesis". Scientific Reports. 4 (1): 5455. doi:10.1038/srep05455. ISSN   2045-2322. PMC   4071322 . PMID   24965831.
  7. 1 2 Dong, Chen-Song; Zhang, Wei-Lun; Wang, Qiao; Li, Yu-Shuai; Wang, Xiao; Zhang, Min; Liu, Lin (2020-04-14). "Crystal structures of cyanobacterial light-dependent protochlorophyllide oxidoreductase". Proceedings of the National Academy of Sciences. 117 (15): 8455–8461. doi: 10.1073/pnas.1920244117 . ISSN   0027-8424. PMC   7165480 . PMID   32234783.
  8. 1 2 Yuichi Fujita and Carl E. Bauer (2000). Reconstitution of Light-independent Protochlorophyllide Reductase from Purified Bchl and BchN-BchB Subunits. J. Biol. Chem., Vol. 275, Issue 31, 23583-23588.
  9. ↑ S.Yamazaki, J.Nomata, Y.Fujita (2006) Differential operation of dual protochlorophyllide reductases for chlorophyll biosynthesis in response to environmental oxygen levels in the cyanobacterium Leptolyngbya boryana. Plant Physiology, 2006, 142, 911-922
  10. ↑ Fujita Y, Matsumoto H, Takahashi Y, Matsubara H (March 1993). "Identification of a nifDK-like gene (ORF467) involved in the biosynthesis of chlorophyll in the cyanobacterium Plectonema boryanum". Plant & Cell Physiology. 34 (2): 305–14. PMID   8199775.
  11. ↑ Nomata J, Ogawa T, Kitashima M, Inoue K, Fujita Y (April 2008). "NB-protein (BchN-BchB) of dark-operative protochlorophyllide reductase is the catalytic component containing oxygen-tolerant Fe-S clusters". FEBS Letters. 582 (9): 1346–50. doi: 10.1016/j.febslet.2008.03.018 . PMID   18358835.
  12. ↑ Muraki N, Nomata J, Ebata K, Mizoguchi T, Shiba T, Tamiaki H, et al. (May 2010). "X-ray crystal structure of the light-independent protochlorophyllide reductase". Nature. 465 (7294): 110–4. Bibcode:2010Natur.465..110M. doi:10.1038/nature08950. PMID   20400946. S2CID   4427639.
  13. 1 2 Zhang, Shaowei; Heyes, Derren J.; Feng, Lingling; Sun, Wenli; Johannissen, Linus O.; Liu, Huanting; Levy, Colin W.; Li, Xuemei; Yang, Ji; Yu, Xiaolan; Lin, Min (2019-10-31). "Structural basis for enzymatic photocatalysis in chlorophyll biosynthesis". Nature. 574 (7780): 722–725. Bibcode:2019Natur.574..722Z. doi:10.1038/s41586-019-1685-2. ISSN   0028-0836. PMID   31645759. S2CID   204849396.
  14. ↑ Moser, Jürgen; Lange, Christiane; Krausze, Joern; Rebelein, Johannes; Schubert, Wolf-Dieter; Ribbe, Markus W.; Heinz, Dirk W.; Jahn, Dieter (2013-02-05). "Structure of ADP-aluminium fluoride-stabilized protochlorophyllide oxidoreductase complex". Proceedings of the National Academy of Sciences. 110 (6): 2094–2098. Bibcode:2013PNAS..110.2094M. doi: 10.1073/pnas.1218303110 . ISSN   0027-8424. PMC   3568340 . PMID   23341615.
  15. ↑ Corless, Elliot I.; Saad Imran, Syed Muhammad; Watkins, Maxwell B.; Bacik, John-Paul; Mattice, Jenna R.; Patterson, Angela; Danyal, Karamatullah; Soffe, Mark; Kitelinger, Robert; Seefeldt, Lance C.; Origanti, Sofia (January 2021). "The flexible N-terminus of BchL autoinhibits activity through interaction with its [4Fe-4S] cluster and released upon ATP binding". Journal of Biological Chemistry. 296: 100107. doi: 10.1074/jbc.RA120.016278 . PMC   7948495 . PMID   33219127.
  16. ↑ Bollivar DW (November 2006). "Recent advances in chlorophyll biosynthesis". Photosynthesis Research. 90 (2): 173–94. doi:10.1007/s11120-006-9076-6. PMID   17370354. S2CID   23808539.

Ferredoxin:protochlorophyllide+reductase+(ATP-dependent) at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

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