Navigation Links
Researchers use neutrons to spy on the elusive hydronium ion
Date:8/8/2011

LOS ALAMOS, New Mexico, August 8, 2011A Los Alamos National Laboratory research team has harnessed neutrons to view for the first time the critical role that an elusive molecule plays in certain biological reactions. The effort could aid in treatment of peptic ulcers or acid reflux disease, or allow for more efficient conversion of woody waste into transportation fuels.

In a paper appearing this week in Angewandte Chemie International Edition, Los Alamos researchers join an international team in describing the role played by the elusive hydronium ion in the transfer of protons during enzyme-catalyzed reactions.

Prior to this research, no one has ever directly witnessed the role of the hydronium ion, a water molecule bound to an additional hydrogen ion, in macromolecular catalyststhe catalytic mechanisms of enzymes.

Researchers took an interest in an enzyme that has the potential to allow conversion of sugars in woody biomass into alcohol, a potential alternative fuel, because the enzyme loses its effectiveness when the pH value of the milieu is lowereda common occurrence in the interior of industrial yeast cells fermenting alcohol. As it turns out, this biochemical reaction also has ramifications for the activation of proton pumps in the stomach, which produces excess acid in those afflicted by gastric diseases.

The scientists sought to figure out the mechanism behind these reactions. Neutrons from the Los Alamos Neutron Science Center provided a possible tool for unveiling the secret agent at the heart of the chemistry.

Hydronium ions had not been seen before by researchers who attempted to use X-rays to understand the chemical mechanism of enzymes. This is because tiny hydrogen atoms are essentially invisible under X-rays. To help make things visible, the researchers substituted hydrogen in their enzyme samples with deuterium, an isotope of hydrogen that behaves chemically identical to its nonisotopic counterpart. Deuterium yields a clear signal when bombarded with neutrons. Therefore, neutrons provided a perfect method for uncloaking the elusive hydronium ions, which appeared as a pyramid-shaped mass in the enzyme's active site where the chemical reaction occurs.

The researchers discovered a crucial change as the system they were studying fell into the acidic range of the pH scale (below 6). The hydronium ion that could be seen facilitating the binding of a metal ion cofactor crucial to the conversion of the sugar molecule into its fermentable form suddenly became dehydratedthink of water, H2O, being removed from hydronium, H3O+. The space occupied by the relatively large hydronium ion collapsed into a tiny volume occupied by the remaining proton (a positively charged hydrogen ion, H+). This spatial change in the molecular structure prevented the sugar from being attacked by the enzyme.

The observed phenomenon provided an answer about why pH plays such an important role in the process and renders the enzyme inactive under acidic conditions. More important, it definitively illustrated that the hydronium ion plays a key role in the transport of protons in these types of biochemical systems.

"This is something that has never been seen before," said Los Alamos researcher Andrey Kovalevsky, principal author of the paper. "This proves that hydronium is the active chemical agent in our studies of the catalytic mechanism of enzymes."

The research has broad implications for the possible role of hydronium ions in other biological systems. In addition to acid reflux disease, the research may help provide a better understanding of metabolic transfer of energy in living cells or living organisms.


'/>"/>

Contact: James E. Rickman
jamesr@lanl.gov
505-665-9203
DOE/Los Alamos National Laboratory
Source:Eurekalert

Related biology news :

1. UGA researchers study threats to white sturgeon
2. Researchers gain new insights into how tumor cells are fed
3. University of Virginia researchers uncover new catalysis site
4. U of Minnesota researchers discover a natural food preservative that kills food-borne bacteria
5. Researchers develop fully cooked food-aid product
6. U of M researchers use improved imaging technique; discover a better approach to diagnosing epilepsy
7. RUB researchers decipher the molecular basis of blue-green algae
8. Researchers discover the mechanism that determines cell position in the intestinal epithelium
9. Caltech researchers increase the potency of HIV-battling proteins
10. Researchers tap yeasts as source of green surfactants
11. Lawson researchers take control of cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/19/2017)... 19, 2017 The global military ... is marked by the presence of several large global ... by five major players - 3M Cogent, NEC Corporation, ... for nearly 61% of the global military biometric market ... the global military biometrics market boast global presence, which ...
(Date:4/11/2017)... PALM BEACH GARDENS, Fla. , April 11, ... biometric identity management and secure authentication solutions, today ... million contract by Intelligence Advanced Research Projects Activity ... technologies for IARPA,s Thor program. "Innovation ... the onset and IARPA,s Thor program will allow ...
(Date:4/5/2017)... , April 5, 2017  The Allen Institute ... Allen Cell Explorer: a one-of-a-kind portal and dynamic digital ... 3D imaging data, the first application of deep learning ... human stem cell lines and a growing suite of ... platform for these and future publicly available resources created ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... DuPont Pioneer and recently ... have entered into a multiyear collaboration to identify and characterize novel CRISPR-Cas nucleases. ... for gene editing across all applications. , Under the terms of the agreement, ...
(Date:10/11/2017)... (PRWEB) , ... October 11, 2017 , ... ... Foundation President Andi Purple announced Dr. Suneel I. Sheikh, the co-founder, CEO ... ASTER Labs ), Inc. has been selected for membership in ARCS Alumni ...
(Date:10/11/2017)...  VMS BioMarketing, a leading provider of patient support solutions, ... Educator (CNE) network, which will launch this week. The VMS ... care professionals to enhance the patient care experience by delivering ... health care professionals to help women who have been diagnosed ... ...
(Date:10/10/2017)... SAN DIEGO, CALIF. (PRWEB) , ... October 10, 2017 , ... ... website as part of its corporate rebranding initiative announced today. The bold new ... broaden its reach, as the company moves into a significant growth period. , It ...
Breaking Biology Technology: