Fingerprints of a gold cluster revealed

Nanometre-scale gold particles are currently intensively investigated for possible applications in catalysis, sensing, photonics, biolabelling, drug carriers and molecular electronics. The particles are prepared in a solution from gold salts and their reactive gold cores can be stabilised with various organic ligands. Particularly stable particles can be synthesised by using organothiolate ligands that have a strong chemical interaction to gold. The chemical process of preparing such particles has been known since the mid-1990s and many different stable sizes and compositions are known.

However, the first definite information of their atomic structure became available only in 2007 when the group of Roger Kornberg (Chemistry Nobel Laureate 2006) at Stanford University succeeded in making single crystals for X-ray diffractometry containing only one type of a particle having 102 gold atoms and 44 thiolate ligands, the so called Au102(p-MBA)44 particle. The structure was reported in Science in late 2007 [1]. The theoretical analysis of this and other thiolate-protected gold clusters, led by Professor Hannu Häkkinen at the University of Jyväskylä in Finland, resulted in a theoretical framework that can be used to understand the stability and electronic structure of these particles. This work was reported in the Proceedings of the National Academy of Sciences in 2008 [2].

Now, researchers in the Department of Chemistry and the Nanoscience Center (NSC) at the University of Jyväskylä, in collaboration with the Kornberg group, report the first full spectroscopic characterisation of the absorption of electromagnetic radiation by the Au102(p-MBA)44 particle in solution and solid phases. The study was published in the Journal of the American Chemical Society on 24 February 2011 [3]. The spectroscopic study was performed in a large range of electromagnetic spectrum from mid-infrared ("heat absorption") to ultraviolet light.

"The study was technically demanding and could only be made now when the Stanford group has succeeded in refining the synthesis to produce pure Au102(p-MBA)44 product in large quantities," explains Adjunct Professor Mika Pettersson, who led the experimental work at the NSC. "We document clear "fingerprint" features in the absorbance spectrum that can be used in the future to benchmark chemical modifications of this particle for various applications. The work also establishes the molecular nature of the clusters by the observation of a band gap of 0.45 eV, in excellent agreement with theory. We were able to analyse these features from large-scale computations using the known structure of Au102(p-MBA)44 and thus fully understand the absorption characteristics of this particle," says Professor Häkkinen.

The other researchers involved in the work are Eero Hulkko, Jaakko Koivisto and Olga Lopez-Acevedo from the University of Jyväskylä. The pure samples of the Au102(p-MBA)44 particle were made by Yael Levi-Kalisman in the Kornberg group. The work at the NSC and the Department of Chemistry at the University of Jyväskylä is funded by the Academy of Finland. The massively parallel computations, using up to 2048 processor cores, were made in the Louhi supercomputer at CSC -- the IT Center for Science.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Academy of Finland, via AlphaGalileo.

Journal References:

P.D. Jadzinsky, G. Calero, C.J. Ackerson, D.A. Bushnell and R.D. Kornberg. Structure of a thiol monolayer-protected gold nanoparticle at 1.1. Angstrom resolution. Science, 318, 430 (2007) DOI: 10.1126/science.1148624Eero Hulkko, Olga Lopez-Acevedo, Jaakko Koivisto, Yael Levi-Kalisman, Roger D. Kornberg, Mika Pettersson, Hannu Ha¨kkinen. Electronic and Vibrational Signatures of the Au102(p-MBA)44Cluster. Journal of the American Chemical Society, 2011; : 110224153619025 DOI: 10.1021/ja111077eM. Walter, J. Akola, O. Lopez-Acevedo, P. D. Jadzinsky, G. Calero, C. J. Ackerson, R. L. Whetten, H. Gronbeck, H. Hakkinen. A unified view of ligand-protected gold clusters as superatom complexes. Proceedings of the National Academy of Sciences, 2008; 105 (27): 9157 DOI: 10.1073/pnas.0801001105

Jewel-toned organic phosphorescent crystals: A new class of light-emitting material

 Pure organic compounds that glow in jewel tones could potentially lead to cheaper, more efficient and flexible display screens, among other applications.

University of Michigan researcher Jinsang Kim and his colleagues have developed a new class of material that shines with phosphorescence -- a property that has previously been seen only in non-organic compounds or organometallics.

Kim and his colleagues made metal-free organic crystals that are white in visible light and radiate blue, green, yellow and orange when triggered by ultraviolet light. By changing the materials' chemical composition, the researchers can make them emit different colors.

The new luminous materials, or phosphors, could improve upon current organic light-emitting diodes (OLEDs) and solid-state lighting. Bright, low-power OLEDs are used in some small screens on cell phones or cameras. At this time, they aren't practical for use in larger displays because of material costs and manufacturing issues.

The OLEDs of today aren't 100 percent organic, or made of carbon compounds. The organic materials used in them must be spiked with metal to get them to glow.

"Purely organic materials haven't been able to generate meaningful phosphorescence emissions. We believe this is the first example of an organic that can compete with an organometallic in terms of brightness and color tuning capability," said Kim, an associate professor of materials science and engineering, chemical engineering, macromolecular science and engineering, and biomedical engineering.

This work is newly published online in Nature Chemistry.

The new phosphors exhibit "quantum yields" of 55 percent. Quantum yield, a measure of a material's efficiency and brightness, refers to how much energy an electron dissipates as light instead of heat as it descends from an excited state to a ground state. Current pure organic compounds have a yield of essentially zero.

In Kim's phosphors, the light comes from molecules of oxygen and carbon known as "aromatic carbonyls," compounds that produce phosphorescence, but weakly and under special circumstances such as extremely low temperatures. What's unique about these new materials is

that the aromatic carbonyls form strong halogen bonds with halogens in the crystal to pack the molecules tightly. This arrangement suppresses vibration and heat energy losses as the excited electrons fall back to the ground state, leading to strong phosphorescence.

"By combining aromatic carbonyls with tight halogen bonding, we achieve phosphorescence that is much brighter and in practical conditions," said Onas Bolton, a co-author of this paper who recently received his Ph.D. in Materials Science and Engineering.

This new method offers an easier way to make high-energy blue organic phosphors, which are difficult to achieve with organometallics.

Organic light emitting diodes are lighter and cheaper to manufacture than their non-organic counterparts, which are made primarily of ceramics. Today's OLEDs still contain small amounts of precious metals, though. These new compounds can bring the price down even further, because they don't require precious metals. They're made primarily of inexpensive carbon, oxygen, chlorine and bromine.

"This is in the beginning stage, but we expect that it will not be long before our simple materials will be available commercially for device applications," Kim said. "And we expect they will bring a big change in the LED and solid-state lighting industries because our compounds are very cheap and easy to synthesize and tune the chemical structure to achieve different colors and properties."

Former doctoral student Kangwon Lee discovered the unique properties of these materials while developing a biosensor -- a compound that detects biological molecules and can be used in medical testing and environmental monitoring. The phosphors have applications in this area as well. After Lee's discovery, Bolton developed the metal-free pure-organic phosphors.

The paper is titled "Activating efficient phosphorescence from purely-organic materials by crystal design." In addition to Kim, Bolton, and Lee, other contributors are: former postdoctoral researcher Hyong-Jun Kim in the Department of Materials Science and Engineering and recent Chemical Engineering graduate Kevin Y. Lin. This work is partly funded by the National Science Foundation and the National Research Foundation of Korea.

The university is pursuing patent protection for the intellectual property, and is seeking commercialization partners to help bring the technology to market.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Michigan.

Journal Reference:

Onas Bolton, Kangwon Lee, Hyong-Jun Kim, Kevin Y. Lin, Jinsang Kim. Activating efficient phosphorescence from purely organic materials by crystal design. Nature Chemistry, 2011; DOI: 10.1038/nchem.984

'Fingerprints' match molecular simulations with reality

A theoretical technique developed at the Department of Energy's Oak Ridge National Laboratory is bringing supercomputer simulations and experimental results closer together by identifying common "fingerprints."

ORNL's Jeremy Smith collaborated on devising a method -- dynamical fingerprints -- that reconciles the different signals between experiments and computer simulations to strengthen analyses of molecules in motion. The research will be published in the Proceedings of the National Academy of Sciences.

"Experiments tend to produce relatively simple and smooth-looking signals, as they only 'see' a molecule's motions at low resolution," said Smith, who directs ORNL's Center for Molecular Biophysics and holds a Governor's Chair at the University of Tennessee. "In contrast, data from a supercomputer simulation are complex and difficult to analyze, as the atoms move around in the simulation in a multitude of jumps, wiggles and jiggles. How to reconcile these different views of the same phenomenon has been a long-standing problem."

The new method solves the problem by calculating peaks within the simulated and experimental data, creating distinct "dynamical fingerprints." The technique, conceived by Smith's former graduate student Frank Noe, now at the Free University of Berlin, can then link the two datasets.

Supercomputer simulations and modeling capabilities can add a layer of complexity missing from many types of molecular experiments.

"When we started the research, we had hoped to find a way to use computer simulation to tell us which molecular motions the experiment actually sees," Smith said. "When we were finished we got much more -- a method that could also tell us which other experiments should be done to see all the other motions present in the simulation. This method should allow major facilities like the ORNL's Spallation Neutron Source to be used more efficiently."

Combining the power of simulations and experiments will help researchers tackle scientific challenges in areas like biofuels, drug development, materials design and fundamental biological processes, which require a thorough understanding of how molecules move and interact.

"Many important things in science depend on atoms and molecules moving," Smith said. "We want to create movies of molecules in motion and check experimentally if these motions are actually happening."

"The aim is to seamlessly integrate supercomputing with the Spallation Neutron Source so as to make full use of the major facilities we have here at ORNL for bioenergy and materials science development," Smith said.

The collaborative work included researchers from L'Aquila, Italy, Wuerzburg and Bielefeld, Germany, and the University of California at Berkeley. The research was funded in part by a Scientific Discovery through Advanced Computing grant from the DOE Office of Science.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by DOE/Oak Ridge National Laboratory.

LED products billed as eco-friendly contain toxic metals, study finds

Those light-emitting diodes marketed as safe, environmentally preferable alternatives to traditional lightbulbs actually contain lead, arsenic and a dozen other potentially hazardous substances, according to newly published research.

"LEDs are touted as the next generation of lighting. But as we try to find better products that do not deplete energy resources or contribute to global warming, we have to be vigilant about the toxicity hazards of those marketed as replacements," said Oladele Ogunseitan, chair of UC Irvine's Department of Population Health & Disease Prevention.

He and fellow scientists at UCI and UC Davis crunched, leached and measured the tiny, multicolored lightbulbs sold in Christmas strands; red, yellow and green traffic lights; and automobile headlights and brake lights.

Their findings? Low-intensity red lights contained up to eight times the amount of lead allowed under California law, but in general, high-intensity, brighter bulbs had more contaminants than lower ones. White bulbs contained the least lead, but had high levels of nickel.

"We find the low-intensity red LEDs exhibit significant cancer and noncancer potentials due to the high content of arsenic and lead," the team wrote in the January 2011 issue of Environmental Science & Technology, referring to the holiday lights. Results from the larger lighting products will be published later, but according to Ogunseitan, "it's more of the same."

Lead, arsenic and many additional metals discovered in the bulbs or their related parts have been linked in hundreds of studies to different cancers, neurological damage, kidney disease, hypertension, skin rashes and other illnesses. The copper used in some LEDs also poses an ecological threat to fish, rivers and lakes.

Ogunseitan said that breaking a single light and breathing fumes would not automatically cause cancer, but could be a tipping point on top of chronic exposure to another carcinogen. And -- noting that lead tastes sweet -- he warned that small children could be harmed if they mistake the bright lights for candy.

Risks are present in all parts of the lights and at every stage during production, use and disposal, the study found. Consumers, manufacturers and first responders to accident scenes ought to be aware of this, Ogunseitan said. When bulbs break at home, residents should sweep them up with a special broom while wearing gloves and a mask, he advised. Crews dispatched to clean up car crashes or broken traffic fixtures should don protective gear and handle the material as hazardous waste. Currently, LEDs are not classified as toxic and are disposed of in regular landfills. Ogunseitan has forwarded the study results to California and federal health regulators.

He cites LEDs as a perfect example of the need to mandate product replacement testing. The diodes are widely hailed as safer than compact fluorescent bulbs, which contain dangerous mercury. But, he said, they weren't properly tested for potential environmental health impacts before being marketed as the preferred alternative to inefficient incandescent bulbs, now being phased out under California law. A long-planned state regulation originally set to take effect Jan. 1 would have required advance testing of such replacement products. But it was opposed by industry groups, a less stringent version was substituted, and Gov. Arnold Schwarzenegger placed the law on hold days before he left office.

"I'm frustrated, but the work continues," said Ogunseitan, a member of the state Department of Toxic Substances Control's Green Ribbon Science Panel. He said makers of LEDs and other items could easily reduce chemical concentrations or redesign them with truly safer materials. "Every day we don't have a law that says you cannot replace an unsafe product with another unsafe product, we're putting people's lives at risk," he said. "And it's a preventable risk."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California - Irvine.

Journal Reference:

Seong-Rin Lim, Daniel Kang, Oladele A. Ogunseitan, Julie M. Schoenung. Potential Environmental Impacts of Light-Emitting Diodes (LEDs): Metallic Resources, Toxicity, and Hazardous Waste Classification. Environmental Science & Technology, 2011; 45 (1): 320 DOI: 10.1021/es101052q

First study of dispersants in Gulf spill suggests a prolonged deepwater fate

To combat last year's Deepwater Horizon oil spill, nearly 800,000 gallons of chemical dispersant were injected directly into the oil and gas flow coming out of the wellhead nearly one mile deep in the Gulf of Mexico. Now, as scientists begin to assess how well the strategy worked at breaking up oil droplets, Woods Hole Oceanographic Institution (WHOI) chemist Elizabeth B. Kujawinski and her colleagues report that a major component of the dispersant itself was contained within an oil-gas-laden plume in the deep ocean and had still not degraded some three months after it was applied.

While the results suggest the dispersant did mingle with the oil and gas flowing from the mile-deep wellhead, they also raise questions about what impact the deep-water residue of oil and dispersant -- which some say has its own toxic effects -- might have had on environment and marine life in the Gulf.

"This study gives our colleagues the first environmental data on the fate of dispersants in the spill," said Kujawinski, who led a team that also included scientists from UC Santa Barbara. "These data will form the basis of toxicity studies and modeling studies that can assess the efficacy and impact of the dispersants.

"We don't know if the dispersant broke up the oil," she added. "We found that it didn't go away, and that was somewhat surprising."

The study, which appears online Jan. 26 in the American Chemical Society (ACS) journal Environmental Science &Technology, is the first peer-reviewed research to be published on the dispersant applied to the Gulf spill and the first data in general on deep application of a dispersant, according to ACS and Kujawinski. Some previous studies had indicated that dispersants applied to surface oil spills can help prevent surface slicks from endangering marshes and coastlines.

Kujawinski and her colleagues found one of the dispersant's key components, called DOSS (dioctyl sodium sulfosuccinate), was present in May and June -- in parts-per-million concentrations--in the plume from the spill more than 3,000 feet deep. The plume carried its mixture of oil, natural gas and dispersant in a southwest direction, and DOSS was detected there at lower (parts-per-billion) concentrations in September.

Using a new, highly sensitive chromatographic technique that she and WHOI colleague Melissa C. Kido Soule developed, Kujawinski reports those concentrations of DOSS indicate that little or no biodegradation of the dispersant substance had occurred. The deep-water levels suggested any decrease in the compound could be attributed to normal, predictable dilution. They found further evidence that the substance did not mix with the 1.4 million gallons of dispersant applied at the ocean surface and appeared to have become trapped in deepwater plumes of oil and natural gas reported previously by other WHOI scientists and members of this research team. The team also found a striking relationship between DOSS levels and levels of methane, which further supports their assertion that DOSS became trapped in the subsurface.

Though the study was not aimed at assessing the possible toxicity of the lingering mixture -- Kujawinski said she would "be hard pressed to say it was toxic" -- it nevertheless warrants toxicity studies into possible effects on corals and deep-water fish such as tuna, she said. The EPA and others have already begun or are planning such research, she added.

David Valentine of UC Santa Barbara and a co-investigator in the study, said, "This work provides a first glimpse at the fate and reactivity of chemical dispersants applied in the deep ocean. By knowing how the dispersant was distributed in the deep ocean, we can begin to assess the subsurface biological exposure, and ultimately what effects the dispersant might have had."

"The results indicate that an important component of the chemical dispersant injected into the oil in the deep ocean remained there, and resisted rapid biodegradation," said Valentine, whose team collected the samples for Kujawinski's laboratory analysis. "This knowledge will ultimately help us to understand the efficacy of the dispersant application, as well as the biological effects."

Kujawinski and Valentine were joined in the study by Soule and Krista Longnecker of WHOI, Angela K. Boysen a summer student at WHOI, and Molly C. Redmond of UC Santa Barbara. The work was funded by WHOI and the National Science Foundation. The instrumentation was funded by the National Science Foundation and the Gordon and Betty Moore Foundation.

In Kujawinski's technique, the target molecule was extracted from Gulf water samples with a cartridge that isolates the DOSS molecule. She and her colleagues then observed the molecule through a mass spectrometer, ultimately calculating its concentration levels in the oil and gas plume. This method is 1,000 times more sensitive than that used by the EPA and could be used to monitor this molecule for longer time periods over longer distances from the wellhead, she said.

"With this method, we were able to tell how much [dispersant] was there and where it went," Kujawinski said. She and her colleagues detected DOSS up to around 200 miles from the wellhead two to three months after the deep-water injection took place, indicating the mixture was not biodegrading rapidly.

"Over 290,000 kg, or 640,000 pounds, of DOSS was injected into the deep ocean from April to July," she said. "That's a staggering amount, especially when you consider that this compound comprises only 10% of the total dispersant that was added."

Kujawinski cautioned that "we can't be alarmist" about the possible implications of the lingering dispersant. Concentrations considered "toxic" are at least 1,000 times greater than those observed by Kujawinski and her colleagues, she said. But because relatively little is known about the potential effects of this type of dispersant/hydrocarbon combination in the deep ocean, she added, "We need toxicity studies."

"The decision to use chemical dispersants at the sea floor was a classic choice between bad and worse," Valentine said. "And while we have provided needed insight into the fate and transport of the dispersant we still don't know just how serious the threat is; the deep ocean is a sensitive ecosystem unaccustomed to chemical irruptions like this, and there is a lot we don't understand about this cold, dark world."

"The good news is that the dispersant stayed in the deep ocean after it was first applied," Kujawinski says. "The bad news is that it stayed in the deep ocean and did not degrade."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Woods Hole Oceanographic Institution.

Journal Reference:

Elizabeth B. Kujawinski, Melissa C. Kido Soule, David L. Valentine, Angela K. Boysen, Krista Longnecker, Molly C. Redmond. Fate of Dispersants Associated with the Deepwater Horizon Oil Spill. Environmental Science & Technology, 2011; : 110126010225058 DOI: 10.1021/es103838p

Hydrogen cartridges fuel laptops and phones for outdoor enthusiasts

 How does a Michigan State University scientist fuel his enthusiasm for chemistry after 60 years? By discovering a new energy source, of course.

This week, SiGNa Chemistry Inc. unveiled its new hydrogen cartridges, which provide energy to fuel cells designed to recharge cell phones, laptops and GPS units. The green power source is geared toward outdoor enthusiasts as well as residents of the Third World, where electricity in homes is considered a luxury.

The spark for this groundbreaking technology came from the laboratory of James Dye, SiGNa's co-founder and University Distinguished Professor of Chemistry Emeritus at MSU. His work with alkali metals led to a green process to harness the power of sodium silicide, which is the source for SiGNa's new product.

"In our lab, we were able to produce alkali metal silicides, which basically are made from sodium and silicon, which, in turn, are produced from salt and sand," Dye said. "By adding water to sodium silicide, we're able to produce hydrogen, which creates energy for fuel cells. The byproduct, sodium silicate, is also green. It's the same stuff found in toothpaste."

SiGNa was able to build on Dye's research and develop a power platform that produces low-pressure hydrogen gas on demand, convert it to electricity via a low-cost fuel cell and emit simple water vapor.

Dye, director of SiGNa's scientific council, said that making the jump to research the company's products was a small one.

"I've been working with alkali metals for 50 years," he said. "My research was closely related to what SiGNa was looking for. So when they came to me with their idea, it was a relatively easy adaptation to make."

Using a similar process, Dye was able to assist the creation of a fuel source to power electric bicycles. The fuel cell, developed by SiGNa's partners, ranges in size from 1 watt to 3 kilowatts and is capable of pushing a bicycle up to 25 mph for approximately 100 miles.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Michigan State University.

Digital signal processing helps researchers get a grip on nervous system's receptors

ScienceDaily (Feb. 8, 2011) — A digital signal processing technique long used by statisticians to analyze data is helping Houston scientists understand the roots of memory and learning, Alzheimer's and Parkinson's diseases and stroke.

Researchers at Rice University and the University of Texas Health Science Center at Houston (UTHealth) reported in the journal Nature Chemical Biology that single molecule fluorescence resonance energy transfer (FRET) techniques combined with wavelet transforms have given them a new view of the AMPA receptor, a glutamate receptor and a primary mediator of fast signal transmission in the central nervous system.

Scientists have long thought these receptor proteins, which bind to glutamate to activate the flow of ions through the nervous system, are more than simple "on-off" switches. A "cleft" in the AMPA protein that looks and acts like a C-clamp and that binds the neurotransmitter glutamate may, in reality, serve functions at positions between fully open (off) and fully closed (on).

"In the old days, the binding was thought to be like a Venus flytrap," said Christy Landes, a Norman Hackerman-Welch Young Investigator Assistant Professor of Chemistry at Rice and lead author of the new paper. "The trap sat there waiting for something to come into the cleft. A neurotransmitter would come in and -- oops! -- it snapped shut on the molecule it was binding to, the gate opened up and ions would flow. We have all sorts of high-quality X-ray crystallography studies to show us what the snapped-open and snapped-shut cleft looks like."

But X-ray images likely show the protein in its most stable -- not necessarily its most active -- conformation, she said. Spectroscopy also has its limits: If half the proteins in an assay are open and half are shut, the measured average is 50 percent, a useless representation of what's really going on.

The truth, Landes said, is that the clefts of AMPA receptors are constantly opening and closing, exploring their space for neurotransmitters. "We know these proteins are super dynamic whether glutamate is present or not," she said. "And we need to look at one protein at a time to avoid averaging."

But seeing single protein molecules go through the motions is well beyond the capability of standard optical tools. That led the researchers to employ a unique combination of technologies. Vasanthi Jayaraman, an associate professor in UTHealth's Department of Biochemistry and Molecular Biology who studies chemical signaling, started the process when she used the binding domain of the AMPA receptor and attached fluorescent dyes to the points of the cleft in a way that would not affect their natural function.

Single-molecule FRET allowed Landes and her team to detect the photons emitted by the dyes. "These experiments had to be done in a box inside a box inside a box in a dark room," she said. "In a short period of measurement, we might be counting 10 photons."

The trick, she said, was to excite only one dye, which would in turn activate the other. "The amount of light that comes out of the dyes has a direct relationship to the distance between the dyes," Landes said. "You excite one, you measure both, and the relative amount of light that comes out of the one you're not exciting depends on how close they are."

Detecting very small changes in the distance between the two points over a period of time required calculations involving wavelets, a tool Rice mathematicians helped develop in the '70s and '80s. (Another recent paper by Landes and Taylor on their wavelet optimization method appears here.)

Wavelets allowed the researchers to increase the resolution of FRET results by reducing shot noise -- distortion at a particular frequency -- from the data. It also allowed them to limit measurements to a distinct time span -- say, 100 milliseconds -- during which the AMPA receptor would explore a range of conformations. They identified four distinct conformations in an AMPA receptor bound to a GluA2 agonist (which triggers the receptor response). Other experiments that involved agonist-free AMPA or AMPA bound to mutated glutamate showed an even floppier receptor.

Knowing how cleft positions match up with the function is valuable, said Jayaraman, who hopes to extend the technique to other signaling proteins with the ultimate goal of designing drugs to manipulate proteins implicated in neurological diseases.

"It was a beautiful combination," she said of the experiments. "We had done a lot of work on this protein and figured out the basic things. What was lacking was this one critical aspect. Being able to collaborate with a physical chemist (Landes) who had the tools allowed us to get details about this protein we wouldn't have seen otherwise."

"Physical chemistry, for all of its existence, amounts to coming up with new tricks to be able to calculate things that nature would not have us calculate," Landes said. "I think our true contribution is to be able to analyze this noisy data to get to what's underneath."

Co-authors of the paper are Anu Rambhadran, a graduate student at UTHealth, and Rice graduate students J. Nick Taylor and Ferandre Salatan.

The American Chemical Society Petroleum Research Fund, the National Institutes of Health and the American Heart Association supported the research.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Rice University.

Journal Reference:

Christy F Landes, Anu Rambhadran, J Nick Taylor, Ferandre Salatan, Vasanthi Jayaraman. Structural landscape of isolated agonist-binding domains from single AMPA receptors. Nature Chemical Biology, 2011; DOI: 10.1038/nchembio.523

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.