Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


At that star, turn left!


Our bodies contain proteins that are made of smaller molecules that can be either left- or right-handed, depending upon their structure. Regardless of which hand we use to write, however, all human beings are `left-handed` at the molecular level. Life on Earth uses the left-handed variety and no one knows how this preference crept into living systems. In 2012, ESA`s Rosetta lander will land on a comet to investigate, among other things, if the origin of this preference lies in the stars.

Living cells use tiny organic molecules (called amino acids) to build proteins in the same way as children build things out of Lego bricks. Most amino acids come in two mirror-image varieties, right- and left-handed. The arrangement of the thumb and four fingers on a left hand is the mirror image of the arrangement on the right. In amino acids, the arrangement of the atoms determines whether the molecule is left- or right-handed.

Uwe Meierhenrich, at the University of Bremen, Germany, thinks that the Earth`s early supply of amino acids came from space, carried by comets. He is part of a European team who reproduced the way organic molecules form in space, to try to understand what the Rosetta lander might find on Comet Wirtanen in 2012.

At a laboratory in Leiden, The Netherlands, they lowered the temperature of a chamber to -261°C, pumped out the air, and injected a rarefied mixture of molecules known to exist in space: water, ammonia, and simple carbon molecules. These molecules froze onto artificial dust grains inside the chamber. They then shone an ultraviolet lamp onto the samples, to simulate starlight. "Our aim was to simulate interstellar conditions as accurately as possible. We did not adapt the conditions to produce amino acids," says Meierhenrich.

Using a version of Rosetta`s Cometary Sampling and Composition (COSAC) experiment, they found newly formed right- and left-handed amino acids in equal quantities. Earthly life, however, uses only left-handed amino acids. Experiments during the 1950s showed that adding right-handed amino acids to proteins stopped the proteins from growing. Was Earth supplied with more left-handed amino acids than right-handed ones in the beginning, allowing life to begin? One famous study has suggested this. Meierhenrich says, "The excess (of left-handed amino acids) found in the Murcheson meteorite is really small and some of the analyses are controversial. Rosetta will give us a much clearer picture."

Some scientists think the key to creating an excess of left over right is in the type of ultraviolet light that shines on the amino acids. When ultraviolet starlight strikes dust grains, it can begin to twist - either clockwise or anticlockwise. Depending on the direction in which it is twisting, it destroys one handedness of amino acid more than the other. In 1998, an international group of astronomers discovered large amounts of `twisty` light occurring naturally in the dusty cocoons of some young stars, where planets might be forming. "I think this is the most probable origin of the excesses," says Meierhenrich who is now using a Paris Laboratory where scientists can twist ultraviolet light to recreate these conditions.

We may well find that Rosetta`s findings on Comet Wirtanen reliably indicate that our molecular left-handedness is indeed a legacy of the stars.

Monica Talevi | alfa
Further information:

More articles from Life Sciences:

nachricht Here comes the long-sought-after iron-munching microbe
25.10.2016 | Max-Planck-Institut für marine Mikrobiologie

nachricht Novel method to benchmark and improve the performance of protein measumeasurement techniques
25.10.2016 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

First-time reconstruction of infectious bat influenza viruses

25.10.2016 | Life Sciences

Novel method to benchmark and improve the performance of protein measumeasurement techniques

25.10.2016 | Life Sciences

Amazon rain helps make more rain

25.10.2016 | Life Sciences

More VideoLinks >>>