Biophysicists at TUM, the Technische Universitaet Muenchen, have published the results of single-molecule experiments that bring a higher-resolution tool to the study of protein folding.
How proteins arrive at the three-dimensional shapes that determine their essential functions – or cause grave diseases when folding goes wrong – is considered one of the most important and least understood questions in the biological and medical sciences.
Folding itself follows a path determined by its energy landscape, a complex property described in unprecedented detail by the TUM researchers. In this week's issue of the Proceedings of the National Academy of Sciences (USA), they report taking hold of a single, zipper-like protein molecule and mapping changes in its energy landscape during folding and unfolding.
Previous studies, including atomic force microscopy experiments by the same Munich laboratory, have gone a long way toward characterizing energy thresholds or barriers that stand between a protein's unfolded and folded states. Detailed observations of the quick transition from one state to the other have remained elusive. The results published this week open the door to higher-resolution, direct measurements. Better characterization of the folding process is seen as a vital link in understanding the chain of events leading from DNA coding for a protein to that protein's biological function. Another motivation for research in this field is the search for new drugs and therapies, because malfunctions in protein folding are implicated in a number of serious diseases – including diabetes, cancer, cystic fibrosis, prion diseases, and Alzheimer's.
This is the latest in a long series of single-molecule biophysical experiments carried out by Professor Matthias Rief and colleagues in the TUM Department of Physics. Co-authors Christof Gebhardt and Thomas Bornschloegl are members of Rief's lab; Gebhardt also is a member of the Munich Center for Integrated Protein Science.
As a model system for studying real-time protein folding dynamics, the TUM scientists chose a so-called leucine zipper found in yeast. It offers, as proteins go, a relatively simple "coiled coil" structure and zipper-like folding action: Picture two amino acid strings side by side, joined at the bottom, open at the top, and made essentially to zip together.
The researchers extended this structure so that they could make independent measurements at the top, bottom, and middle parts of the zipper. They took hold of the free ends at the top of the zipper with handles made of double-stranded DNA. These DNA handles in turn were attached to tiny beads that could be directly manipulated by "optical tweezers" – a tool based on the ability of laser beams with a certain kind of profile to pin down nanoscale objects. One end of the protein molecule was held fixed, and the other was held under tension but with some freedom to move, so that folding dynamics could be measured directly, in real time, as the protein zipped and unzipped. This arrangement enabled measurements with high resolution in both space and time.
"What I consider the major improvement is that the new experiments allow the observation of thousands of transitions between the folded and the unfolded state," Rief said. "This enables us to detect not only the folded and unfolded states but also, directly, the excursions of the large energy barriers separating those states. This has previously been impossible, and it now allows direct insight into the precise energy profile of this barrier."
Publication: Full distance resolved folding energy landscape of one single protein molecule, by J. Christof M. Gebhart, Thomas Bornschloegl, and Matthias Rief, PNAS Early Edition for the week of Jan. 18, 2010.
Contact:Prof. Matthias Rief
Patrick Regan | EurekAlert!
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences