More VRML Chelates
This noframe version has been provided as a courtesy to those who use a frame-incapable or frame-disabled
browser. Frames contribute to the utilization of this site because they permit a text window to reside
beside a graphics (VRML) window, offering explanation as to its contents. A properly installed VRML
plugin, such as Live3D, CosmoWorld, or WorldView is required for viewing of the 3D graphics component
of this page.
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 from the root
environment for uptake by the plant. Mugineic acid is closely related to its
nicotinamine, 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 binding coordinating groups are two amine-N, two
carboxylate-O, and one a-hydroxycarboxylate site (two O), a total of 2 N's
and 4 O's, forming a tight octahedron in which the central Fe(III) atom resides.
CPK Color Key: gray, carbon; red, oxygen; blue, nitrogen; purple, iron. Hydrogen
atoms have been removed for clarity.
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.
Ma, JF, and K Nomoto. 1996. Effective regulation of iron
acquisition in graminaceous plants. The role of mugineic acids as phytosiderophores.
Physiol. Plant. 97:609-617.
Mino, Y, et al. 1983. Mugineic acid-iron(III) complex and its structurally
analogous cobalt(III) complex: Characterization and implication for absorption and transport of iron
in graminaceous plants. J. Am. Chem. Soc. 105:4671-4676. [crystal structure]
Dept. of Soil Science,
University of Wisconsin-Madison. All rights reserved to author.
Images and text may not be stored on another server without permission.
Last modified (NoFrame version) 28 July 1997.