Siderophores from Bacteria and from Fungi
Herbert Budzikiewicz
from: Iron Uptake and Homeostasis in Microorganisms (Edited by: Pierre Cornelis and Simon C. Andrews). Caister Academic Press, U.K. (2010)
Abstract
In the early days of life on earth due to the emergence of photosynthesis, the atmosphere became oxidative and so iron prevailed in its trivalent form. The consequence was that most microorganisms live today in a surrounding where the concentration of soluble iron compounds is much too low to satisfy their physiological needs. One of the possibilities to circumvent this problem is the production of so-called siderophores, compounds which can form water soluble complexes with Fe3+. They are released in situations of iron deficiency. Fe3+ possesses six coordination sites arranged in the shape of an octahedron which can accommodate three bidentate ligands. The major ligand types are catecholates, hydroxamates and α-hydroxycarboxylates, in the ideal case connected by adequate spacers which keep them in the correct position. Many siderophores have elaborate structures which can bind to the cell surface of the producing species. In this way pirating by competing microorganisms is rendered more difficult read more ...
