scholarly journals Catalytic Protein Film Electrochemistry Provides a Direct Measure of the Tetrathionate/Thiosulfate Reduction Potential

2015 ◽  
Vol 137 (41) ◽  
pp. 13232-13235 ◽  
Author(s):  
Julia M. Kurth ◽  
Christiane Dahl ◽  
Julea N. Butt
Keyword(s):  
Reduction Potential ◽  
Direct Measure ◽  
Protein Film ◽  
Thiosulfate Reduction

Influence of electrochemical properties in determining the sensitivity of [4Fe-4S] clusters in proteins to oxidative damage

2001 ◽  
Vol 360 (3) ◽  
pp. 717-726 ◽  
Author(s):  
Gareth J. TILLEY ◽  
Raul CAMBA ◽  
Barbara K. BURGESS ◽  
Fraser A. ARMSTRONG
Keyword(s):  
Oxidative Damage ◽  
Structural Changes ◽  
Reduction Potential ◽  
Azotobacter Vinelandii ◽  
Pyrococcus Furiosus ◽  
Protein Film ◽  
Protein Film Voltammetry ◽  
Thauera Aromatica ◽  
Key Factor ◽  
Ferredoxin I

Interconversion between [4Fe-4S] cubane and [3Fe-4S] cuboidal states represents one of the simplest structural changes an iron–sulphur cluster can undertake. This reaction is implicated in oxidative damage and in modulation of the activity and regulation of certain enzymes, and it is therefore important to understand the factors governing cluster stability and the processes that activate cluster conversion. In the present study, protein film voltammetry has been used to induce and monitor the oxidative conversion of [4Fe-4S] into [3Fe-4S] clusters in different variants of Azotobacter vinelandii ferredoxin I (AvFdI; the 8Fe form of the native protein), and ΔThr14/ΔAsp15, Thr14 → Cys (T14C) and C42D mutants. The electrochemical results have been correlated with the differing oxygen sensitivities of [4Fe-4S] clusters, and comparisons have been drawn with other ferredoxins (Desulfovibrio africanus FdIII, Clostridium pasteurianum Fd, Thauera aromatica Fd and Pyrococcus furiosus Fd). In contrast with high-potential iron–sulphur proteins (HiPIPs) for which the oxidized species [4Fe-4S]3+ is inert to degradation and can be isolated, the hypervalent state in these ferredoxins (most obviously the 3+ level) is very labile, and the reduction potential at which this is formed is a key factor in determining the cluster's resistance to oxidative damage.

Electron Microscopy of Nucleic Acids

1974 ◽  
Vol 32 ◽  
pp. 302-303
Author(s):  
Norman Davidson
Keyword(s):  
Electron Microscopy ◽  
Nucleic Acids ◽  
Basic Protein ◽  
Molecular Biologist ◽  
Topological Properties ◽  
Protein Film ◽  
Polynucleotide Chain

The basic protein film technique for mounting nucleic acids for electron microscopy has proven to be a general and powerful tool for the working molecular biologist in characterizing different nucleic acids. It i s possible to measure molecular lengths of duplex and single-stranded DNAs and RNAs. In particular, it is thus possible to as certain whether or not the nucleic acids extracted from a particular source are or are not homogeneous in length. The topological properties of the polynucleotide chain (linear or circular, relaxed or supercoiled circles, interlocked circles, etc. ) can also be as certained.

Octafluoro[2.2]paracyclophane (AF4) Quinone

2008 ◽  
Vol 73 (12) ◽  
pp. 1764-1776
Author(s):  
Wei Xu ◽  
William R. Dolbier ◽  
Jian-Xin Duan ◽  
Yian Zhai ◽  
Katsu Ogawa ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Reduction Potential ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction

Octafluoro[2.2]paracyclophane (AF4) has been oxidized by treatment with HIO3 in CF3CO2H to form the corresponding p-quinone along with a unique triketone. This quinone undergoes reduction to the respective hydroquinone as well as a Diels-Alder reaction with 1,3-cyclohexadiene. Its reduction potential was obtained by cyclic voltammetry and is discussed in the context of other quinones.

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