Siderophores complexes

Although Fe is required as a trace element, its uptake is critically regulated since excess leads to the generation of toxic hydroxyl radicals, and complex interactions involving Fe(II) and Fe(HI) exist within the cell (Touati et al. 1995). The role of Fe(III)-complexing siderophores in maintaining homeostasis has been noted in Chapter 3, Part 5. Details of the role of Fe and its relation to the... 

Fig. 5 Typical cyclophane receptors for metal ion complexation (siderophore 31. torand 32, crown ether 36), onium ion-rt interactions (33, crpptophane 38). hydrogen bonding interactions (34-37), and chiral recognition (36-38). Self-assembled cyclophanes 39 and 40.

Raymond, K. N., Muller, G., and Matzanke, B. F. Complexation of Iron by Siderophores A Review of Their Solution and Structural Chemistry and Biological Function. 123 49-102 (1984). 

Complexation of iron by siderophores. A review of their solution and structural chemistry and biological function. K. N. Raymond, G. Muller and B. F. Matzanke, Top. Curr. Chem., 1984,123, 49 (227). 

Henry M, Jolivet JP, Livage J (1991) Aqueous Chemistry of Metal Cations Hydrolysis, Condensation and Complexation. 77 153-206 Hider RC (1984) Siderophores Mediated Absorption of Iron. 57 25-88 Hill HAO, Rdder A, Williams RJP (1970) The Chemical Nature and Reactivity of Cytochrome P-450. 8 123-151... 

Under aerated conditions at neutral to alkaline pH, inorganic iron is extremely insoluble (8), such that plants and microorganisms rely absolutely on iron uptake from organic matter complexes or iron that has been solubilized by siderophores and organic compounds contained in root exudate. Low-molecular-weight root exudates that dissolve iron include organic acids that are secreted by plant roots as a specific response to iron deficiency (9) or that are released constitutively at... 

Plant and microbial competition for iron involves very complex interactions that are influenced by a number of factors (Fig. 2). These include differences in the level of siderophore production by all of the competing microorganisms, the chciTiical stabilities of various siderophores and other chelators with iron, their... 

Siderophore production by rhizosphere bacteria that are culturable on agar media has been estimated by plating out colonies on an indicator agar medium containing chrome azurol, a weak iron-chelating complex that changes color upon... 

Siderophores are iron-complexing compounds of low molecular weight that are synthesized by bacteria and fungi, and serve to deliver iron to the microbes. Because of their exclusive affinity and specificity for Fe3+, natural siderophores and synthetic derivatives have been exploited in the treatment of human iron-overload diseases. The most successfully used example is Desferal , which is the methane sulfonate derivative of iron-free ferrioxamine B, a linear trihydroxamate (Figure 3.2). Ferrioxamine was isolated in 1958 from the culture supernatant of Streptomyces... 

Figure 3.2 Chemical structures of selected siderophores to demonstrate the four major structural classes and the different solutions of microorganisms to scavenge iron. See for comparison the conformations of the Fe3+-complexes of ferrichrome and albomycin shown in Figure 3.5.

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