A study that teases apart the biological mechanisms by which human papillomaviruses (HPV) cause cancer has found what researchers at Georgetown University Medical Center say is a new strategy that might provide targeted treatment for these cancers. HPV is responsible for the majority of cer ... more
Cellular Communication Agent
Tracking the NO signaling pathway
Both nitric oxide (NO) and hydrogen sulfide (H2S) act as gaseous signaling molecules with similar physiological effects. Many of the critical questions about the interplay between these two gasotransmitters hinge on their chemical reactivity and the fleeting existence of HSNO, a key product of the reaction between them. A team of researchers has been able to stabilize, isolate, and characterize two of the species tied to these signaling pathways through binding to a zinc complex, as reported in the journal, Angewandte Chemie.
NO is a central signaling molecule in biology that regulates many physiological functions that include vascular dilation, transmission of nerve impulses, and cell protection. Interestingly, H2S exhibits similar effects, relaxing smooth muscle cells involved in vasodilation. HSNO may thus play a key role in the overlap of these signaling pathways. This extremely reactive species is so unstable, however, that its biochemistry and discrete reaction pathways are very difficult to determine. HSNO passes readily through cell membranes and can nitrosylate proteins, transferring its nitrosyl group (–N=O) to other residues, especially cysteine, which represents an important step in a number of cellular regulation mechanisms. At biological pH, HSNO likely exists as the thionitrite anion SNO− that is unstable towards conversion to the perthionitrite anion SSNO−.
Graduate student Valiallah Hosseininasab in the team led by Timothy H. Warren at Georgetown University (Washington, D.C., USA) stabilized the SNO− and SSNO− anions through binding to a special zinc complex inspired by a common environment for zinc in biology. Zinc is a physiologically important metal that is involved in myriad processes that include the regulation of blood pH through the enzyme carbonic anhydrase. Moreover, molecules involved in nitric oxide signaling, such as H2S and S-nitrosothiols (molecules with an –S–N=O group), readily react with zinc–sulfur bonds that form important structural units whose modification in proteins leads to functional change.
The Georgetown team revealed that zinc complexes containing the SNO− and SSNO− anions could be isolated and characterized. Investigation of their reactivity patterns showed interesting differences in their reactions with thiols (substances with a sulfide group, –SH), ubiquitous antioxidants that help protect cells from damage. While reactions with perthionitrite form NO, thionitrite forms either dinitrogen oxide (laughing gas) N2O or S-nitrosothiols, which represent ready reservoirs of NO. These results suggest that the smallest differences in the course of physiological signaling pathways can lead to different output signals that ultimately result from the interplay between NO and H2S.
- nitric oxide
- hydrogen sulfide
- signalling molecules
Scientists in the United States have developed a sensor that could be used to help develop more efficient catalysts for producing chiral compounds in industry. In research they describe the preparation of inexpensive palladium complexes that provide a sensitive UV signal in the presence of ... more
With the goal of tailoring cancer interventions for the individual, researchers at the Lombardi Comprehensive Cancer Center at Georgetown have published the results of a prospective study that validates the use of a simple blood test to help doctors more reliably assess treatment effectiven ... more
Many natural products are complicated organic molecules. Despite this complexity, scientists are usually able to investigate them using spectroscopic techniques. However, a team of researchers has now discovered that care should be taken using Raman spectroscopy to analyze certain chiral mo ... more
Photoinduced charge transfers are an interesting electronic property of Prussian blue and some analogously structured compounds. A team of researchers has now been able to elucidate the ultrafast processes in the light-induced charge transfer between iron and manganese in a manganese-contai ... more
Scientists can monitor biomolecular processes in live tissue by noninvasive optical methods, such as fluorescence imaging. However, the fluorescent dyes used for that purpose are often rather unstable, and photobleaching, lack of specificity, and poor pharmacokinetics are recurrent issues. ... more
- 1Detect neurodegenerative diseases such as Alzheimer's by a simple eye scan?
- 2Fluorescence microscopy at highest spatial and temporal resolution
- 3The Mechanics of the Immune System
- 4Resolve Biosciences Launches New Era in Single-Cell Spatial Analysis
- 5Quick look under the skin
- 6New ion trap to create the world's most accurate mass spectrometer
- 7How does your computer smell?
- 8Clocking electron movements inside an atom
- 9Sartorius closes 2020 with strong growth
- 10A clear path to better insights into biomolecules
- Nature-inspired coatings could power tiny chemistry labs for medical testing ...
- ‘Feeling’ the living cell’s life cycle using optical tweezers
- Researchers have succeeded for the first time in analyzing nanovesicles and ...
- Scientists discover how bacteria use liquid protein droplets to overcome stress
- New tool can identify harmful blue-green algae