(Press-News.org) The protein α-synuclein is one of the most abundant proteins in the human brain. It is often referred to as the "Parkinson protein", as deposition of this protein in brain cells is a hallmark of Parkinson's disease. Despite the high interest of biomedical research in the protein, many questions concerning the function and physiology of α-synuclein in living cells still remain to be answered. For example, it was previously unclear whether and to what extent the protein binds to and interacts with internal cell components such as membranes. As such processes could play a role in the development of the disease, the team led by Konstanz-based physical chemist Professor Malte Drescher used the further development of an established measurement method called "electron paramagnetic resonance spectroscopy" (EPR spectroscopy) to learn more about the binding properties of the "Parkinson protein". The study, published in the scientific periodical "The Journal of Physical Chemistry Letters", furnishes proof of concept that the advanced method is fundamentally suitable for elucidating protein-lipid interactions in cells. Furthermore, this first practical test yielded direct evidence of the binding of α-synuclein to intracellular membranes.
Slower is not always more thorough
The advanced version of EPR spectroscopy, in the current study used for the first time in practice, is called rapid-scan EPR spectroscopy. In both methods, the conventional and the advanced, the proteins to be studied are first fitted with so-called spin probes. These chemical probes make it possible to detect changes in protein structure. Spin probes each have a free electron whose spin is excited by irradiation with microwaves. "We can imagine spins as small compass needles that are influenced by microwave irradiation during the measurement," Drescher explains. In conventional EPR spectroscopy, for each group of excited spins it is necessary to wait until this influence decays before the group can be excited again. This relatively time-consuming process must be repeated over many passes to achieve the complete measurement.
With rapid-scan EPR spectroscopy, by contrast, it is no longer necessary to wait until the influence on a spin group abates before continuing the measurement. "Instead, you rush the influence spectrally from spin group to spin group and then return to the first group at the very moment when its excitation has just subsided," says Drescher. On the one hand, this procedure shortens the required measurement time, while on the other it allows application of higher microwave power, leading to improved accuracy of the method. The researchers have made use of both of these advantages in their current study on the binding behaviour of α-synuclein.
The new method in practice
From previous studies conducted in vitro ("in the test tube") it was already known that the "Parkinson protein" α-synuclein can attach itself to electrically negatively charged lipid membranes. In EPR spectroscopy, this binding process is accompanied by a characteristic change in the measured signal. "The initially disordered α-synuclein assumes an ordered form upon binding to the membrane. This reduces the mobility of the spin probe, and the binding of the protein can be directly detected by the measurement method," explains Theresa Braun, doctoral student in Drescher's research team and, jointly with Juliane Stehle, lead author of the study.
Using synthetic, negatively charged membrane vesicles and purified α-synuclein, Drescher and his colleagues were able to detect the same signal change in rapid-scan EPR spectroscopy. However, they succeeded not only in vitro, but also inside cells of the African clawed frog (Xenopus laevis), into which first the artificial membrane vesicles were introduced and, a short time later, the protein was. The research team then carried out time-dependent measurements and was able to directly observe, based on the change in the measurement signal, how the proportion of the protein bound in the cell increased over time.
A comparable - albeit significantly weaker - increase in the amount of bound α-synuclein over time was also seen when no artificial membranes were introduced into the cell. Thus, according to Drescher, only one explanation remained for this crucial observation. "This is the first time that we see direct evidence that α-synuclein interacts with the endogenous, i.e. naturally existing lipid membranes as well," the scientist concludes. Due to the comparatively small size of the effect, in experiments with less precise measurement methods this had previously remained hidden.
From frog to human
In future studies, Malte Drescher's team plans to build on this result and further elucidate the process of intracellular binding of α-synuclein to natural cell components, in order to learn more about the function of the protein. An important step in this process will be the move from frog cells as a model system to various mammalian cell types. The long-term goal is to better understand the protein-lipid interactions of the "Parkinson protein" and its role in the development of Parkinson's disease in order to be able to develop suitable therapeutic approaches.
INFORMATION:
The research work took place within the framework of the Konstanz Collaborative Research Centre 969 "Chemical and biological principles of cellular proteostasis" and received additional funding from the "Horizon 2020" framework programme of the European Union.
Key facts:
* Original publication: Theresa S. Braun, Juliane Stehle, Sylwia Kacprzak, Patrick Carl, Peter Höfer, Vinod Subramaniam, Malte Drescher, Intracellular Protein-Lipid Interactions Studied by Rapid-Scan Electron Paramagnetic Resonance Spectroscopy, DOI: 10.1021/acs.jpclett.0c03583
* Link: https://doi.org/10.1021/acs.jpclett.0c03583
* Feasibility study for direct detection of protein-lipid interactions in living cells using rapid-scan EPR spectroscopy
* First direct detection of the binding of α-synuclein to intracellular membrane lipids
* Future research is expected to further elucidate the binding of α-synuclein to natural cell membranes and be extended to include a variety of mammalian cell types
* Project cooperation of the University of Konstanz and the Free University of Amsterdam (Netherlands) in collaboration with Bruker BioSpin
* Project coordination: Professor Malte Drescher, Professor of Physical Chemistry at the University of Konstanz.
* Funded by the German Research Foundation (DFG; within the framework of SFB 969) and the European Research Council (ERC; within the framework of Horizon 2020).
An article published by the researchers of the Biodiversity Unit at the University of Turku, Finland, highlights how amateur venom-extraction business is threatening scorpion species. Sustainably produced scorpion venoms are important, for example, in the pharmacological industry. However, in the recent years, there has been a dramatic increase in the number of people involved in the trade and vast numbers of scorpions are harvested from nature. This development is endangering the future of several scorpion species in a number of areas.
Scorpions have existed on Earth for over 430 million years. Currently comprising over 2,500 extant species, scorpions occur on almost all the major landmasses in a range of habitats from ...
Gravity is the weakest of all known forces in nature - and yet it is most strongly present in our everyday lives. Every ball we throw, every coin we drop - all objects are attracted by the Earth's gravity. In a vacuum, all objects near the Earth's surface fall with the same acceleration: their velocity increases by about 9.8 m/s every second. The strength of gravity is determined by the mass of the Earth and the distance from the center. On the Moon, which is about 80 times lighter and almost 4 times smaller than the Earth, all objects fall 6 times slower. And on a planet of the size of a ladybug? ...
A new study published Tuesday 10 March, No Smoking Day, from King's College London highlights the 'clear benefit' of using e-cigarettes daily in order to quit smoking, and supports their effectiveness when compared to other methods of quitting, including nicotine replacement therapy or medication.
Although the number of people in England who smoke has continued to fall in recent years, tobacco smoking is still the leading preventable cause of premature death and disease - killing nearly 75,000 people in England in 2019.
While e-cigarettes have been around for more than a decade, evidence on their effectiveness for helping people to ...
There's a surprising amount of information stored in the hardened plaque, or calculus, between teeth. And if that calculus belongs to the remains of a person who lived in ancient times, the information could reveal new insights about the past. But the tiny samples can be difficult to work with. Now, in ACS' Journal of Proteome Research, scientists apply a new method to this analysis, finding more proteins than traditional approaches.
The human mouth is full of interesting molecules: DNA and enzymes in saliva, proteins and lipids from bits of food stuck between teeth, the bacterial ...
Amsterdam, NL, March 10, 2021 - Music-based interventions have become a core ingredient of effective neurorehabilitation in the past 20 years thanks to the growing body of knowledge. In this END ...
People are different. New technology is good for patients and the healthcare system. But it could also expand the already significant health disparities in Norway and other countries.
"Women and men with higher education in Norway live five to six years longer than people with that only have lower secondary school education," says Emil Øversveen, a postdoctoral fellow at the Norwegian University of Science and Technology's (NTNU) Department of Sociology and Political Science.
He is affiliated with CHAIN, the Centre for Global Health Inequalities Research. The centre works to reduce social health ...
In the dry air and soil of Texas' Southern High Plains, improving soil health can be tough. We usually think of healthy soil as moist and loose with lots of organic matter. But this can be hard to achieve in this arid area of Texas.
Lindsey Slaughter, a member of the Soil Science Society of America, set out with her fellow researchers to test a solution that kills two birds with one stone. They put excess cow manure on these soils to see if they could make them healthier.
The team recently published their research in the Soil Science Society of America Journal.
"We know that planting perennial grasslands for cattle production can help protect and restore soil in semi-arid lands that are likely to erode and degrade from intense ...
The per-capita rates of new COVID-19 cases and COVID-19 deaths were higher in states with Democrat governors in the first months of the pandemic last year, but became much higher in states with Republican governors by mid-summer and through 2020, possibly reflecting COVID-19 policy differences between GOP- and Democrat-led states, according to a study led by researchers at the Johns Hopkins Bloomberg School of Public Health and the Medical University of South Carolina.
For their study, the researchers analyzed data on SARS-CoV-2-positive nasal swab tests, COVID-19 diagnoses, and COVID-19 ...
Immune cells specialize to ensure the most efficient defense against viruses and other pathogens. Researchers at the University of Basel have shed light on this specialization of T cells and shown that it occurs differently in the context of an acute and a chronic infection. This could be relevant for new approaches against chronic viral infections.
Researchers led by Professor Carolyn King of the University of Basel have developed a method to study the specialization of T cells in the context of infections. In the journal eLife, they report the different directions ...
The scientists of the National University of Science and Technology "MISIS" (NUST MISIS) being a part of an international team of researches managed to increase the capacity and extend the service life of lithium-ion batteries. According to the researchers, they have synthesized a new nanomaterial that can replace low-efficiency graphite used in lithium-ion batteries today. The results of the research are published in the Journal of Alloys and Compounds.
Lithium-ion batteries are widely used for household appliances from smartphones to electric vehicles. The charge-discharge cycle in such battery is provided by ...
