Mugineic-acid 3-dioxygenase

Mugineic-acid 3-dioxygenase
Identifiers
EC no.1.14.11.25
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Mugineic-acid 3-dioxygenase (EC 1.14.11.25, IDS2) is an enzyme with systematic name mugineic acid,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating).[1][2] This enzyme catalyses the following chemical reaction

 
Fe(IV)=O
Fe(II)
 
 
 
3-epi-3-hydroxymugineic acid

It can also catalyse the related reaction:[3]

2'-deoxymugineic acid
 
Fe(IV)=O
Fe(II)
 
 
 
3-epi-3-hydroxy-2'-deoxymugineic acid

Mugineic acid is an amino acid excreted by some graminaceous (grassy) plants under conditions of iron deficiency as part of a strategy of solubilizing Fe(III) from the root environment for uptake by the plant. Mugineic acid is closely related to its biochemical precursor, nicotianamine, and to a number of other compounds that also have been identified as phytosiderophores in graminaceous plants: 3-hydroxymugineic acid, 2'-deoxymugineic acid, avenic acid, and distichonic acid.

The effectiveness of mugineic acid under iron-deficient conditions is dependent not only upon the iron chelating properties of the Fe-mugineic acid complex itself but also upon the presence of a plant membrane carrier that recognizes and absorbs the Fe-mugineic acid complex almost exclusively.[4]

Mechanism

The enzyme is a 2-oxoglutarate-dependent oxygenase, which are non-heme iron proteins with ferryl active site where Fe(IV)=O is the species that transfers its oxygen to the substrate.[5]

The mechanism requires 2-oxoglutaric acid to activate the iron oxygen complex, and this gives succinic acid and carbon dioxide when the second atom of the molecular oxygen is removed.[6][7]

 
[O]
CO2
 
 
 

References

  1. ^ Nakanishi H, Yamaguchi H, Sasakuma T, Nishizawa NK, Mori S (September 2000). "Two dioxygenase genes, Ids3 and Ids2, from Hordeum vulgare are involved in the biosynthesis of mugineic acid family phytosiderophores". Plant Molecular Biology. 44 (2): 199–207. doi:10.1023/A:1006491521586. PMID 11117263. S2CID 26139505.
  2. ^ Okumura N, Nishizawa NK, Umehara Y, Ohata T, Nakanishi H, Yamaguchi T, Chino M, Mori S (July 1994). "A dioxygenase gene (Ids2) expressed under iron deficiency conditions in the roots of Hordeum vulgare". Plant Molecular Biology. 25 (4): 705–19. Bibcode:1994PMolB..25..705O. doi:10.1007/BF00029608. PMID 8061321. S2CID 20143807.
  3. ^ Enzyme 1.14.11.25 at KEGG Pathway Database.
  4. ^ Barak, Phillip. "Mugineic acid, a phytosiderophore". Archived from the original on 2011-08-28. Retrieved 2026-03-14.
  5. ^ Mbenza NM, Vadakkedath PG, McGillivray DJ, Leung IK (December 2017). "NMR studies of the non-haem Fe(II) and 2-oxoglutarate-dependent oxygenases". J. Inorg. Biochem. 177: 384–394. doi:10.1016/j.jinorgbio.2017.08.032. PMID 28893416.
  6. ^ Hibi M, Ogawa J (May 2014). "Characteristics and biotechnology applications of aliphatic amino acid hydroxylases belonging to the Fe(II)/α-ketoglutarate-dependent dioxygenase superfamily". Applied Microbiology and Biotechnology. 98 (9): 3869–3876. doi:10.1007/s00253-014-5620-z. PMID 24682483.
  7. ^ Clifton IJ, Hsueh LC, Baldwin JE, Harlos K, Schofield CJ (2001). "Structure of proline 3-hydroxylase. Evolution of the family of 2-oxoglutarate dependent oxygenases". Eur. J. Biochem. 268 (24): 6625–36. doi:10.1046/j.0014-2956.2001.02617.x. PMID 11737217.