Iron-sulfur clusters dinuclear

There are many other proteins that contain iron in a form that is neither in haem nor in iron-sulfur clusters. We have already encountered the iron storage and transport proteins, ferritin and transferrin (see Chapter 8). We propose to discuss here two other classes of iron-containing proteins, those with mononuclear non-haem iron centres and those with dinuclear non-haem iron centres. 

A more specific operational definition excludes the unique clusters of the nitrogenase enzymes (which are treated in Chapter 7) from our considerations biological iron-sulfur clusters in this context only deal with Fe and do not contain any other metal. Under physiological conditions they can occur in two, and not more than two, oxidation states. All clusters are either dinuclear or one of the... 

The discovery of the different dinuclear or cuboidal-type biological iron-sulfur clusters is associated with their natural occurrence in two oxidation states. They can all function as one-electron transferring agents. This redox function has been well established in many studies over a period of almost five decades [1-5], However, electron transfer is generally not considered to be a catalytic activity. It is typically a stoichiometric transfer between two complex redox proteins. Mechanistically, it is probably best described as outer sphere or not involving the breaking and making of covalent bonds other than those related to hydrons. 

Iron-sulfur cluster compounds, 1203 dinuclear, 235 electrochemistry, 236 hexanuclear, 241 mononuclear, 235 tetranuclear, 238 trinuclear, 237 Isomerization iridium catalysts, 1158... 

Fig. 4. Simplified diagram, illustrating the proposed oxidation states and coordination of the [NiFe]-dinuclear center in D. gigas hydrogenase. States with the highest oxidation level are at the top, each lower level representing reduction by one equivalent. The redox states of the Fe-S clusters are not shown, e represents electrons exchanged with the iron-sulfur clusters H+ protons from exchange with the proton channels.

Spin ladders, 38 180-183 Spin-lattice relaxation, 13 205 iron-sulfur centers, 47 486-487 dinuclear clusters, 47 435-436 HiPlP, 47 447... 

Chalcogenides Solid-state Chemistry Copper Enzymes in Denitrification Copper Hemocyanin/Tyrosinase Models Copper Proteins Oxidases Copper Proteins with Dinuclear Active Sites Copper Proteins with Type 1 Sites Copper Proteins with Type 2 Sites Iron-Sulfur Models of Protein Active Sites Iron-Sulfur Proteins Nickel Enzymes Cofactors Nickel Models of Protein Active Sites Polynuclear Organometallic Cluster Complexes. 

There are hundreds of iron-containing enzymes. In general, the iron can exist as (a) a mononuclear site, in which it is coordinated by a tetrapyrrole structure (hemes) or strictly by amino acid residues that donate oxo, nitrogen, or sulfur ligands (b) a dinuclear site in which the irons are bridged by oxo, nitrogen, or sulfur coordination (c) a trinuclear site as in the 3Fe-4S clusters or (d) a tetranuclear site as in the [4Fe-4S] clusters. 

The [FeFe]-hydrogenases have been known since the 1930s [305], and Warburg recognized sulfur-coordinate iron as an essential element of the enzyme [306]. The [FeFe]-hydrogenase from Clostridium pasteurianum accommodates 20 iron atoms organized in one [2Fe-2S] cluster, three [4Fe S] clusters and the so-called H-cluster which is a [4Fe-4S] cluster covalently linked to a dinuclear [FeFe]... 

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