Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Secret of Efficient Photosynthesis is Decoded

Published: Wednesday, May 15, 2013
Last Updated: Wednesday, May 15, 2013
Bookmark and Share
MIT researchers find that the key to purple bacteria’s light-harvesting prowess lies in highly symmetrical molecules.

Purple bacteria are among Earth’s oldest organisms, and among its most efficient in turning sunlight into usable chemical energy. Now, a key to their light-harvesting prowess has been explained through a detailed structural analysis by scientists at MIT.

A ring-shaped molecule with an unusual ninefold symmetry is critical, the researchers found. The circular symmetry accounts for its efficiency in converting sunlight, and for its mechanical durability and strength. The new analysis, carried out by professors of chemistry Jianshu Cao and the late Robert Silbey, postdoc Liam Cleary, and graduate students Hang Chen and Chern Chuang, has been published in the Proceedings of the National Academy of Sciences.

“The symmetry makes the energy transfer much more robust,” Cao says. “Most biological systems are quite soft and disordered. You would not expect a regular structure, almost a perfect structure,” as is found in this primitive microbe, he says.

In these regular round complexes, Cao says, “nature only used certain symmetry numbers: mostly ninefold, some eightfold, very few tenfold. It’s very selective.” His group’s mathematical analysis shows there are good reasons for that, he says.

These ring-shaped molecules, in turn, are arranged in a hexagonal pattern on the spherical photosynthetic membrane of purple bacteria, Cao says.

“With these symmetry numbers, the interactions between all pairs of the symmetric rings are optimized at the same time. … We believe that nature found the most robust structures in terms of energy transfer,” Cao says. Both eightfold and tenfold symmetries also work, though not as well: Only a lattice made up of ninefold symmetric complexes can tolerate an error in either direction. “You want consecutive numbers so it can tolerate such mistakes,” Cao says.

The molecular system in question, called light-harvesting complex 2 (LH2), operates in waterborne organisms that do not produce oxygen; such species consume sulfides, often found in volcanic hot springs or in deep-sea hydrothermal vents. LH2 molecules release energy when struck by photons; that energy is then stored as molecules of ATP that can later be used as fuel for metabolism.

The structure of LH2 complexes had previously been determined by other groups, Cao explains. “What we provide is an explanation of why nature selected such a structure,” he says. “What is the advantage compared to other possible structures?”

Now that the reasons for this molecule’s efficiency in harvesting light have been deciphered, Cao says, researchers can take advantage of its symmetries to create synthetic systems for harvesting solar energy. “We can design large molecules, with similar high-symmetry motifs, that can facilitate energy transfer,” he says.

The new analysis showed how the hexagonal arrangement of molecules on the bacteria’s membrane surface enhanced their performance by matching the ninefold symmetry of LH2. “Most of the focus in the past has been on the individual molecules,” Cao says, adding, “We are taking this lesson we learned from nature to explore design principles. If I want to design a superlattice of nanotubes or nanowires, what is the best internal structure and what is the best crystal order? We consider symmetry matching in the context of the larger structure.”

While this research focused on a specific type of light-harvesting molecule, the underlying principles of energy-transfer efficiency may be applicable to charge transfer, heat transport and other processes, Cao says.

Stuart Rice, a professor of chemistry at the University of Chicago, says this work is “an inspired analysis and prediction for synthetic materials that is itself inspired by a biological process and system. I have not ever before seen the question of the relationship between energy-transfer efficiency and complexity of packing treated as in this paper. … This is a brilliant analysis that should find immediate acceptance.”

Rice adds that this research “opens the door to a new way of designing efficient synthetic photosensitive devices, by coupling internal structure to packing in a fashion that is not now involved in the design process.”

The research was supported by the National Science Foundation; the Defense Advanced Research Projects Agency; and the MIT Center for Excitonics, funded by the Department of Energy.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,900+ scientific posters on ePosters
  • More Than 5,300+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

New Method for Analyzing Crystal Structure
Exotic materials called photonic crystals reveal their internal characteristics with new method.
Monday, November 28, 2016
Biomarker Guiding Cancer Therapy
Biologists link levels of Mena protein to breast cancer cells’ sensitivity to chemotherapy.
Tuesday, November 22, 2016
Capsule Achieves Long-Term Drug Delivery
Novel drug delivery method could aid in elimination of malaria and treatment of many other diseases.
Monday, November 21, 2016
Synthetic Cells Isolate Genetic Circuits
Encapsulating molecular components in artificial membranes offers more flexibility in designing circuits.
Tuesday, November 15, 2016
Turning Greenhouse Gas into Gasoline
New catalyst provides design principles for producing fuels from carbon dioxide emissions.
Tuesday, November 15, 2016
New Approach Against Salmonella
Researchers have developed a strategy to immunize against microbes that invade the gastrointestinal tract, including Salmonella.
Tuesday, November 08, 2016
Laser Particles Could Provide Sharper Tissue Images
New imaging technique stimulates particles to emit laser light, could create higher-resolution images.
Tuesday, November 08, 2016
Engineers Design New Weapon Against Bacteria
Researchers have successfully engineered antimicrobial peptides that can kill bacterial strains resistant to existing antibiotics.
Thursday, November 03, 2016
Predicting Cancer Cells’ Response to Chemotherapy
Researcher develop method for testing cell ability to perform different types of DNA repair, which can reveal tumors’ sensitivity to drugs.
Wednesday, November 02, 2016
Nanobionic Spinach Detects Dangerous Chemicals
Scientists have changed spinach plants into biosensors that can detect harful chemicals and wirelessly relay the information.
Tuesday, November 01, 2016
Fighting Cancer with the Power of Immunity
Researchers at MIT have used a combination of four different therapies to activate both of the immune system’s two branches, producing a coordinated attack that led to the complete disappearance of large, aggressive tumors in mice.
Friday, October 28, 2016
Fighting Cancer with Immune Response
New treatment elicits two-pronged immune response that destroys tumors in mice.
Tuesday, October 25, 2016
MRIs for Fetal Health
Algorithm could help analyze fetal scans to determine whether interventions are warranted.
Monday, October 24, 2016
Mapping Serotonin in the Living Brain
Imaging technique that creates a 3D video of serotonin transport could aid antidepressant development.
Monday, October 24, 2016
Achieving “Green” Desalination
Workshop explores ways to reduce or eliminate the carbon footprint of seawater desalination plants.
Thursday, October 20, 2016
Scientific News
Big Genetics in BC: The American Society for Human Genetics 2016 Meeting
Themes at this year's meeting ranged from the verification, validation, and sharing of data, to the translation of laboratory findings into actionable clinical results.
Stem Cells in Drug Discovery
Potential Source of Unlimited Human Test Cells, but Roadblocks Remain.
Cancer Genetics: Key to Diagnosis, Therapy
When applied judiciously, cancer genetics directs caregivers to the right drug at the right time, while sparing patients of unnecessary or harmful treatments.
BGI Sequences Gingko Tree, Revealing Large, Highly Repetitive Genome
Researchers at BGI have sequenced the more than 10-gigabase ginkgo genome to find a high number of repetitive sequences as well as a number of gene clusters that appear to be involved in defense mechanisms.
Survey of New York City Soil Uncovers Medicine-Making Microbes
Microbes have long been an invaluable source of new drugs. And to find more, we may have to look no further than the ground beneath our feet.
Accelerating the Detection of Foodborne Bacterial Outbreaks
The speed of diagnosis of foodborne bacterial outbreaks could be improved by a new technique developed by researchers at the Georgia Institute of Technology.
Making Personalized Medicine a Reality
Groundbreaking technique developed at McMaster University is helping to pave the way for advances in personalized medicine.
Scientists Identify Unique Genomic Features in Testicular Cancer
The findings may shed light on factors in other cancers that influence their sensitivity to chemotherapy.
Top 10 Life Science Innovations of 2016
2016 has seen the release of some truly innovative products. To help you digest these developments, The Scientist have listed their top picks for the year.
BioCision Forms MedCision
The new company will focus on technologies for the management and automation of vital clinical processes.
Scroll Up
Scroll Down
Skyscraper Banner

SELECTBIO Market Reports
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
5,300+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!