Redox-sensing proteins

The transcriptional repressor Rex is a redox-sensing protein playing a role in the shift from acidogenesis to solventogenesis in C. acetobutylicum [102]. Rex controls the expression of butanol biosynthetic genes in response to NADH/NAD" ratio in the cell [102,103]. Rex is also present in C. beijerinckii [103] and in C. saccharobutylicum as well as C. saccharoperbutylacetonicum (BLAST analysis using JGI/IMG website). 

Wietzke, M. and Bahl, H. (2012) The redox-sensing protein Rex, a transcriptional regulator of solventogenesis in Clostridium acetobutylicum. Appl. Microbiol. Biotechnol, 96, 749-761. 

There is a wider general interest in understanding the oxidation of cysteine thiolates in proteins since they are involved in redox-sensing reactions [99], Therefore, such oxidation reactions of thiols induced by Ru coordination may also play a more general role in the pharmacological activity of Ru-arene complexes by coupling Ru coordinative binding to redox processes both outside and inside cells. 

Key words Halorhodospira halophila, Ectothiorhodospira, Elalobacterium salinarum, Rhodobacter sphaeroides, Synechocystis, Rhodocista centenaria, Rhodospirillum centenum. Swimming motility, Swarming motility. Twitching motility. Photoactive yellow protein, Sensory rhodopsin, Phytochrome, BLUF, Redox sensing... 

Holderman MT, Miller KP, Dangott LJ, Ramos KS Identification of albumin precursor protein, Phi AP3, and alpha-smooth muscle actin as novel components of redox sensing machinery in vascular smooth muscle cells. Mol Pharmacol 2002, 61 1174-1183. 

Another method for the analysis of aptamer-protein complexes involved the use of a positively charged ferrocene-tethered polythiophene, (19), as redox label reporting unit (Fig. 12.19). The antithrombin aptamer was immobilized on an electrode surface, and the electrostatic binding of the redox polymer (19) to the aptamer monolayer resulted in a supramolecular complex that revealed electrical contact between the polymer and the electrode.74 The formation of the aptamer-thrombin complex removed the polymer from the surface and blocked the electrical contact between the polymer label and the electrode. As a result, higher concentrations of thrombin increased the surface coverage of the aptamer-thrombin complex on the electrode, and this decreased the amperometric responses of the sensing device. 

Rusnak, F. and T. Reiter. 2000. Sensing electrons Protein phosphatase redox regulation. Tr. Biochem. Sci. 25 527-9. 

Numerous transition metals ions form cluster complexes with chalcogenide anions [42-52], Iron and sulphur are unique elements in the sense that no two other elements can generate such a large diversity of cluster structures. This is the consequence of two stable oxidation states of iron ions and strong Fe-S bonds of significantly covalent character [53], Moreover, numerous structures are stable in several oxidation states, so these clusters serve as electron reservoirs in biological systems [51], This is why iron-sulphur proteins usually catalyze redox reactions. 

In fact, one of the most interesting discoveries of the past decade is that Fe S clnsters are used as sensors for a variety of different types of environmental stimuli and use a wide range of sensing mechanisms involving cluster assembly, transfer, conversion, or redox chemistry to perturb protein structure. 

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