Iron-sulfur proteins and enzymes are unique because they possess one or more iron-sulfur clusters. They are ubiquitous in nature, playing key roles in photosynthesis, nitrogen fixation, and terminal respiration, not to mention a host of other biologically important reactions including CO oxidation to CO2, interconversion of H2 and H+, and sulfite/nitrite reduction. Historically, most studies focused on the electron-transferring properties of iron-sulfur proteins, but now several enzymes have been discovered that clearly use iron-sulfur clusters for catalysis. The iron-sulfur clusters in these proteins and enzymes are usually coordinated to the polypeptide by the amino acid cysteine in its thiolate form, —CH2S-. Inorganic sulfide (S2-“acid labile sulfide”) is required for the formation of the clusters, except for the special case fo Fe(SCH2HR4H)4-containing proteins. While these are single iron proteins which do not contain a metal cluste, they are generally included in the iron-sulfur proteins. Iron-sulfur proteins can then be characterized by considering the type and quantity of iron-sulfur clusters they possess. The most common encountered clusters types found in iron-sulfur proteins are shown in Fig. 1.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Electrochemistry of iron-sulfur proteins
Benjamin A. Feinberg
Michael D. Ryan
- Birkhäuser Basel
- Chapter 6
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