Reduction/oxidation (redox) systems research is reaching a stage where domains that traditionally belonged to the physical sciences, chemistry, and molecular biology are coming together to offer new synergistic opportunities for understanding and manipulating basic cellular processes that underlie complex biomedical problems (e.g., tumorigenesis).
Parallel with this advance is the emerging recognition that the intracellular redox environment exerts a profound influence on the normal cellular processes of DNA synthesis, enzyme activation, selective gene expression, cell cycle progression, proliferation, differentiation, and apoptosis. However, this is a difficult area of study and molecular mechanisms mediating redox sensitivity are poorly defined.
An interdisciplinary research team from the University of Illinois’ Institute for Genomic Biology (IGB) report in the February issue of the journal Experimental Biology and Medicine the engineering of novel peptide sequences that are sensitive to redox conditions inside cells.
“Attachment of linkers between a special pair of green fluorescent proteins (GFP) shows great promise for developing genetically encoded redox sensitive biosensors,” said Vladimir L. Kolossov, corresponding author. To detect oxidation and reduction, the biosensor uses a powerful optical technique called Förster resonance energy transfer (FRET).
The absence of polypeptide linkers able to sense the redox state by undergoing a conformational change was the major obstacle to a FRET-based redox sensor. The researchers designed the linker sequence such that in its reduced state the linker is an α-helix. Thiol groups, strategically placed throughout the linker, sense the redox potential of the environment and form disulfide bonds upon oxidation.
Under oxidative conditions intramolecular disulfide bonds can form, shifting the free energy minimum from the α-helix, to a “clamped-coil” state (similar to a helix-coil transition). The coiled state allows the two fluorescent proteins to approach closer than in the extended helix state, where they can more efficiently exchange excitation energy (i.e., a high FRET state). The extent of energy transfer is easily quantified from the increased emission of the acceptor.
This is the first step towards development of a FRET-based biosensor for visualizing redox potentials and oxidative stress in live cells and tissues via optical microscopy.
“We employed a sensitive technique for measuring FRET to screen our linkers. This methodology greatly expedited the quantitative analysis and development of the linkers and will be very useful for the development of other FRET-based sensors,” said Bryan Q. Spring, a doctoral student and co-author of the publication. Given the importance of the intracellular redox state in determining a cell’s fate, and the increasing evidence that perturbations in the redox state are associated with cancer and various inflammatory disorders as well as aging, FRET-based redox sensors offer significant promise for understanding molecular mechanisms underlying human health and disease.
Dr. Steven R. Goodman, Editor-in-Chief of Experimental Biology and Medicine, said “Altered redox status is a hallmark of many diseases ranging from neurological disorders, such as Alzheimer’s Disease, to hematologic disorders such as Sickle Cell Disease. The development of a FRET-based biosensor to measure oxidative stress in living cells would be of enormous benefit to biomedical researchers working in many diverse fields. This is precisely the type of interdisciplinary effort that the new Experimental Biology and Medicine hopes to provide to the international scientific community.”
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20.10.2017 | Naval Research Laboratory
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
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The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
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