Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Two-Legged Molecule

25.04.2012
A small molecule moves independently along a track

Within each of the cells in our bodies, and between individual cells, there are permanent transport processes occurring over distances ranging from a few nanometers to several millimeters.

One of these cellular “cargo carriers” works by means of molecular motors that “walk” along the filaments of the cellular skeleton (cytoskeleton). British researchers have used these as inspiration to develop a molecular “track”, along which a small molecule can move back and forth like a courier. Their system is described in the journal Angewandte Chemie.

David A. Leigh and a team at the University of Edinburgh (UK) made their track from an oligoethylenimine. The filament contains amino groups that act as “stepping-stones” for the molecular “walker”. The walker is a small molecule (á-methylene-4-nitrostyrene). It resembles a stick figure that has an aromatic six-membered ring of carbon atoms for its torso, a nitro group for its head, and two short hydrocarbon legs.

The molecule is initially bound to the first stepping-stone of the track by one leg. The molecular walker’s movement begins with a ring-closing rearrangement (an intramolecular Michael reaction). This causes the second leg to bind to the neighboring stepping-stone. A second, ring-opening rearrangement reaction (a retro-Michael reaction) then causes the first leg to detach from its stepping-stone. This allows the molecular walker to move along the track step by step.

There is, however, a catch: All of these rearrangement reactions are equilibrium reactions.

If the stepping-stones are chemically equivalent, the tiny walker swings back and forth, lifts one leg and puts it down again, moves forward one step then back again; its movement has no directionality. However, it manages on average an amazingly high 530 “steps” before completely coming off the track. That is significantly more than natural systems like the kinesin motor proteins.

The miniature walker can even carry out a task: The researchers attached an anthracene group to the end of a track with five stepping-stones. As long as the walker stays at the beginning of the track, the anthracene fluoresces. However, if the walker reaches the anthracene end of the track, an electronic interaction between the walker and the anthracene “switches off” the fluorescence. The researchers found that the intensity of the fluorescence slowly sinks by about half. The final intensity is reached after about 6.5 hours, at which point there is an equilibrium between all possible positions of the walker.

The team’s next goal is to develop a walker that uses a “fuel” to march in a predetermined direction to transport cargoes over longer, branched tracks.

About the Author
Professor David Leigh is the Forbes Chair of Organic Chemistry at the University of Edinburgh. He is one of the international leaders in the field of artificial molecular motors and machines. He is a Fellow of the Royal Society (the UK's National Academy of Sciences) and has received the 2007 international Feynman Award for Nanotechnology, and many other distinctions. His group is moving to the University of Manchester in autumn 2012.
Author: David A. Leigh, University of Edinburgh (UK), http://www.catenane.net/
Title: A Small Molecule that Walks Non-Directionally Along a Track Without External Intervention

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201200822

David A. Leigh | Angewandte Chemie
Further information:
http://www.catenane.net/
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

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,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>