Protochlorophyllide reductase

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light-dependent protochlorophyllide reductase
Identifiers
EC number1.3.1.33
CAS number68518-04-7
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
light-independent protochlorophyllide reductase
Dpor.png
Crystallographic structure of heterooctamer of a dark-operative protochlorophyllide oxidoreductase from Prochlorococcus marinus.[1]
Identifiers
EC number1.3.7.7
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum

In enzymology, protochlorophyllide reductases (EC 1.3.1.33 and EC 1.3.7.7) are enzymes that catalyzes the chemical reaction

protochlorophyllide + NADPH + H+ chlorophyllide a + NADP+

Thus, the three substrates of this enzyme are protochlorophyllide, NADPH, and H+, whereas its 2 products are chlorophyllide a and NADP+ .

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class 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. This enzyme participates in porphyrin and chlorophyll metabolism.

There are two structurally unrelated proteins with this activity, referred to as light-dependent and the dark-operative. The light-dependent reductase needs light to function, while the dark-operative version is a completely different protein, consisting of three subunits that exhibit significant sequence similarity to the three subunits of nitrogenase.[2] This enzyme might be evolutionary older but (being similar to nitrogenase) is highly sensitive to free oxygen and does not work if its concentration exceeds about 3%.[3] Hence the alternative, light dependent version needed to evolve.

References[edit]

  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. ^ Yuichi FujitaDagger 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. [1]
  3. ^ 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 [2]