An international team of biologists led by Indiana University's David M. Kehoe has identified both the enzyme and molecular mechanism critical for controlling a chameleon-like process that allows one of the world's most abundant ocean phytoplankton, once known as blue-green algae, to maximize light harvesting for photosynthesis.
Responsible for contributing about 20 percent of the total oxygen production on the planet, the cyanobacteria Synechococcus uses its own unique form of a sophisticated response called chromatic acclimation to fine tune the absorption properties of its photosynthetic antenna complexes to the predominant ambient light color. The researchers identified and characterized an enzyme, MpeZ, that plays a pivotal role in the mechanism that allows two different water-soluble proteins in Synechococcus -- phycoerythrin I and II -- to alter their pigmentation in order to maximize photon capture for photosynthesis.
Scientists want to understand how cyanobacteria optimize their photosynthetic activities in different light conditions to gain a better appreciation of how human activities affect the phytoplankton's ability to produce oxygen and uptake the greenhouse gas carbon dioxide, which they consume in order to grow. Science and industry also use the pigment-protein complex phycoerythrin for fluorescent imaging and as fluorescent markers in biotechnology and health care applications.
"We now have the ability to attach a novel chromophore, part of a molecule responsible for its color, to phycoerythrin, which provides a new chromophore-protein combination that absorbs and fluoresces at a wavelength that is not currently commercially available," said Kehoe, a professor in the IU Bloomington College of Arts and Sciences' Department of Biology. "Our results suggest that this new chromoprotein is brighter and more stable than most on the market today."
Kehoe also noted IU has begun the process of filing a patent on the invention.
The team found that the gene encoding the MpeZ enzyme is activated in blue light. Once produced, MpeZ then binds to antenna proteins containing pigments that normally catch green light and attaches an alternative chromophore that allows the antennae to capture blue light. The specific mechanism, called type IV chromatic acclimation, involves replacing three molecules of the green light-absorbing chromophore with an equal number of blue light-absorbing chromophore. This color-shifting is reversible and is controlled by the ratio of blue to green light in the environment.
"These 'chromatic adapters' are true chameleons that can efficiently live in green coastal waters as well as in blue offshore waters by modifying their pigmentation," Kehoe said. "Synechococcus cells maintained in blue light harvest preferentially blue light, while cells grown in green light harvest more green."
"A phycoerythrin-specific bilin lyase-isomerase controls blue-green chromatic acclimation in marine Synechococcus" was published online in the Nov. 12 Early Edition of Proceedings of the National Academy of Science. Co-authors with Kehoe, also affiliated with IU Bloomington's Indiana Molecular Biology Institute, were IU Ph.D. student Animesh Shukla; Avijit Biswas and Wendy M. Schluchter of the University of New Orleans; Nicolas Blot of Université Pierre et Marie Curie - Paris 06, the Centre National de la Recherche Scientifique and Clermont Université in France; Frederic Partensky and Laurence Garczarek of Université Pierre et Marie Curie - Paris 06 and the Centre National de la Recherche Scientifique; IU Bloomington Department of Chemistry METACyt Biochemical Analysis Center mass spectrometry facility manager and assistant scientist Jonathan A. Karty and assistant scientist Loubna A. Hammad; and former IU biology graduate student Andrian Gutu, now of Harvard University.
Funding for this work came from the Agence Nationale Recherches in France, the European program MicroB3, IU's Office of International Programs, the National Science Foundation and the Lilly Foundation.
For more information or to speak with Kehoe, please contact Steve Chaplin, IU Communications, at 812-856-1896 or email@example.com.
Steve Chaplin | Source: EurekAlert!
Further information: www.iu.edu
More articles from Life Sciences:
New way to improve antibiotic production
18.06.2013 | Norwich BioScience Institutes
Missing enzyme linked to drug addiction
18.06.2013 | The Endocrine Society
... two engines aircraft project “Elektro E6”.
The countdown has been started for opening the gates again for the worldwide leading aviation and space event in Le Bourget, Paris from June 17th - 23rd, 2013.
EADCO & PC-Aero will present at the Paris Air Show in Hall H4 booth F-7 their new future aircraft and innovative project: ...
Siemens scientists have developed new kinds of ceramics in which they can embed transformers.
The new development allows power supply transformers to be reduced to one fifth of their current size so that the normally separate switched-mode power supply units of light-emitting diodes can be integrated into the module's heat sink.
The new technology was developed in cooperation with industrial and research partners who ...
Cheaper clean-energy technologies could be made possible thanks to a new discovery.
Led by Raymond Schaak, a professor of chemistry at Penn State University, research team members have found that an important chemical reaction that generates hydrogen from water is effectively triggered -- or catalyzed -- by a nanoparticle composed of nickel and phosphorus, two inexpensive elements that are abundant on Earth. ...
The Fraunhofer Institute for Laser Technology ILT generated a lot of interest at the LASER World of Photonics 2013 trade fair with its numerous industrial laser technology innovations.
Its highlights included beam sources and manufacturing processes for ultrashort laser pulses as well as ways to systematically optimize machining processes using computer simulations. There was even a specialist booth at the fair dedicated to the revolutionary technological potential of digital photonic production.
Now in its fortieth year, LASER World ...
It's not reruns of "The Jetsons", but researchers working at the National Institute of Standards and Technology (NIST) have developed a new microscopy technique that uses a process similar to how an old tube television produces a picture—cathodoluminescence—to image nanoscale features.
Combining the best features of optical and scanning electron microscopy, the fast, versatile, and high-resolution technique allows scientists to view surface and subsurface features potentially as small as 10 nanometers in size.
The new microscopy technique, described in the journal AIP Advances,* uses a beam of electrons to excite a specially ...
18.06.2013 | Materials Sciences
18.06.2013 | Health and Medicine
18.06.2013 | Life Sciences
14.06.2013 | Event News
13.06.2013 | Event News
10.06.2013 | Event News