Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Molecular Breakdance of Seeing

17.11.2015

Our sense of vision is based on highly choreographed, ultrafast molecular motions.

The detection of light by pigments in the retina, called rhodopsin or visual purple, leads to our sense of vision. New experiments by scientists from the Max Planck Institute for the Structure and Dynamics of Matter and the University of Toronto have revealed that the primary photochemical event of this process operates at the fundamental molecular speed limit. These results are reported online in the journal Nature Chemistry today.


Artist's impression of the molecular motion in the retina.

J.M. Harms, MPSD

The retinal chromophore in rhodopsin, also called vitamin A aldehyde, derives its light sensitivity from a repeating chain of single- and double-bonded carbon atoms. The absorption of a photon by retinal causes an extremely short transient weakening of a specific double bond resulting in rotation about that bond.

Pinpointing how fast this so-called chemical isomerization reaction occurs has been difficult, however, and has largely tracked the technological advances in pulsed laser sources. With femtosecond lasers it was shown that the isomerization takes place within 200 femtoseconds (that is 200 millionths of a billionth of a second), and is likely a vibrationally-coherent chemical reaction, meaning the vibrational motions of the retinal chromophore itself help directing the isomerization reaction.

Using a highly sensitive technique from the field of ultrafast spectroscopy called heterodyne-detected transient grating spectroscopy, scientists in the laboratories of Professors R. J. Dwayne Miller (University of Toronto and Max Planck Institute for the Structure and Dynamics of Matter) and Oliver P. Ernst (University of Toronto) revisited the isomerization reaction of bovine rhodopsin with unprecedented sensitivity and temporal resolution.

Such an approach revealed that the isomerization takes place on a timescale of 30 femtoseconds. “It turns out that the primary step of vision is nearly ten times faster than anyone thought,” says Professor Miller, “and the atomic motions are all perfectly choreographed by the protein.”

Temporal analysis of the experimental data revealed these choreographed vibrational dynamics, which are comprised of localized stretching, out-of-plane wagging, and torsional motions. “Such a fast timescale sets distinct limitations on the vibrationally-coherent reaction coordinate,” says Dr. Philip Johnson, lead author of the study, "and this work indicates that it is local to the specific isomerizing double bond.”

“Moreover,” he adds, “the isomerization reaction proceeds within a single period of the relevant torsional vibrational motion. The notion of fully vibrationally-coherent chemical reactions has been around since at least the 1930s, but really hasn't been explicitly observed until now.”

This research was supported by the Max Planck Society, the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Excellence Research Chairs program (CERC), and the Canadian Institute for Advanced Research (CIFAR). Professor Miller and Professor Ernst are co-directors of CIFAR’s program Molecular Architecture of Life, which is untangling the details of the complex molecular processes that underlie all living systems.

Contact person:
Prof. Dr. R. J. Dwayne Miller
Max Planck Institute for the Structure and Dynamics of Matter
Center for Free-Electron Laser Science
Luruper Chaussee 149
22761 Hamburg
Germany
+49 (0)40 8998-6200
dwayne.miller@mpsd.mpg.de

Original publication:
Philip J. M. Johnson, Alexei Halpin, Takefumi Morizumi, Valentyn I. Prokhorenko, Oliver P. Ernst, and R. J. Dwayne Miller, “Local vibrational coherences drive the primary photochemistry of vision,” Nature Chemistry 7, 980–986 (2015), DOI: 10.1038/nchem.2398

Weitere Informationen:

http://dx.doi.org/10.1038/nchem.2398 Original publication
http://www.mpsd.mpg.de/mpsd/research/ard Research group of Prof. Dr. R. J. Dwayne Miller
http://www.mpsd.mpg.de/en Max Planck Institute for the Structure and Dynamics of Matter

Dr. Michael Grefe | Max-Planck-Institut für Struktur und Dynamik der Materie

More articles from Life Sciences:

nachricht Full of hot air and proud of it
18.04.2018 | University of Pittsburgh

nachricht Keeping the excitement under control
18.04.2018 | Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

Im Focus: Stronger evidence for a weaker Atlantic overturning

The Atlantic overturning – one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards – is weaker today than any time before in more than 1000 years. Sea surface temperature data analysis provides new evidence that this major ocean circulation has slowed down by roughly 15 percent since the middle of the 20th century, according to a study published in the highly renowned journal Nature by an international team of scientists. Human-made climate change is a prime suspect for these worrying observations.

“We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coast – which is highly characteristic for a slowdown of the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

New capabilities at NSLS-II set to advance materials science

18.04.2018 | Materials Sciences

Strong carbon fiber artificial muscles can lift 12,600 times their own weight

18.04.2018 | Materials Sciences

Polymer-graphene nanocarpets to electrify smart fabrics

18.04.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>