The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

Investigations of the oxidative disassembly of Fe-S clusters in Clostridium pasteurianum 8Fe ferredoxin using pulsed-protein-film voltammetry.

Rapid responses of biological [4Fe-4S] clusters to conditions of oxidative stress have been studied by protein-film voltammetry by using precise pulses of electrode potential to trigger reactions. Investigations with Clostridium pasteurianum 8Fe ferredoxin exploit the fact that [3Fe-4S] clusters display a characteristic pattern of voltammetric signals, so that their appearance and disappearance after an oxidative pulse can be tracked unambiguously under electrochemical control. Adsorbed to monolayer coverage at a graphite electrode, the protein initially shows a strong signal (B') at -0.36 V vs standard hydrogen electrode due to two [4Fe-4S](2+/+) clusters at similar potentials. Short square pulses (0.1-5 s) to potentials in the range 0.5-0.9 V cause extensive loss of B', and new signals appear (A'and C') that arise from [3Fe-4S] species (+/0 and 0/2- couples). The A' and B' intensities quantify transformations which are induced by the pulse and which occur subsequently when more reducing conditions are restored. Optimal [3Fe-4S] formation (in excess over [4Fe-4S]) is achieved with a 3-s pulse to 0.7 V, following which there is rapid partial recovery to yield a 1:1 3Fe:4Fe ratio, consistent with 7Fe protein. Thus, a 6Fe protein is formed, but one of the clusters is rapidly repaired. The [3Fe-4S]:[4Fe-4S] ratio follows a bell-shaped curve spanning the same potential range that defines complete loss of signals, while double-pulse experiments show that [3Fe-4S](+) resists further oxidative damage. Oxidative disassembly involves successive one-electron oxidations of [4Fe-4S] (i.e., 2+ --> 3+ --> 4+), with [3Fe-4S](+) being a relatively stable byproduct, that is, not an intermediate. Disassembly of [3Fe-4S] in the 7Fe protein continues after reducing conditions are restored, with lifetimes depending on oxidation level; thus 1+ (most stable) > 0 > 2-. In the presence of Fe(2+), the 0 level is stabilized by conversion back to [4Fe-4S](2+/+). By pulsing in the presence of Zn(2+), the [3Fe-4S] clusters that are formed are trapped rapidly as their Zn adducts.[1]


WikiGenes - Universities