Navigation Links
In an enzyme critical for life, X-ray emission cracks mystery atom
Date:11/17/2011

ITHACA, N.Y. - Like a shadowy character just hidden from view, a mystery atom in the middle of a complex enzyme called nitrogenase had long hindered scientists' ability to study the enzyme fully.

But now an international team of scientists led by Serena DeBeer, Cornell assistant professor of chemistry and chemical biology, has pulled back the curtain using powerful synchrotron spectroscopy and computational modeling to reveal carbon as the once-elusive atom.

The research was published online Nov. 17 in the journal Science.

"For chemists, one of the first steps you want to be able to take is to actually model the site," said DeBeer. "It turns out that the chemistry of how this cluster behaves will be different depending on what atom is in the middle. This is the first step toward trying to unravel its mechanism."

Why nitrogenase? In nature, all life requires the element nitrogen from the atmosphere to form amino acids and build proteins. Bacteria need to convert nitrogen to ammonia as a precursor to more complex biosynthetic processes. The enzyme that catalyzes all this is nitrogenase, and it does it by breaking one of the strongest bonds in chemistry the nitrogen triple bond.

The chemical industry has figured out how to convert nitrogen to ammonia in high-temperature and high-pressure industrial environments. There's a fascination with understanding how the enzyme makes this same process work in nature, DeBeer said.

DeBeer and colleagues honed in on a subset of atoms in the relatively large enzyme, called the iron-molybdenum cofactor, which was thought to be the site where dinitrogen (N2) gets converted to ammonia, and where the mystery atom is situated inside.

The team used a method called X-ray emission spectroscopy (XES) at the Stanford Synchrotron Radiation Light Source to excite the electrons in the cofactor's iron cluster and to watch how electrons refilled the spots, called "holes," they left behind. The holes were sometimes filled by an electron belonging to a neighboring atom emitting X-ray signatures with distinct ionization potentials that would distinguish between different kinds of atoms.

This was how it was revealed that the cofactor contained a carbon atom, rather than a nitrogen or an oxygen atom, that was bound to the iron atoms in the cluster.


'/>"/>
Contact: Blaine Friedlander
bpf2@cornell.edu
607-254-8093
Cornell University
Source:Eurekalert

Related biology news :

1. Atomic-resolution views suggest function of enzyme that regulates light-detecting signals in eye
2. New insight into the controls on a go-to enzyme
3. UNC scientists teach enzyme to make synthetic heparin in more varieties
4. Rare disease provides clues about enzyme role in arrhythmias
5. Brain enzyme may play key role in controlling appetite and weight gain
6. Newly found enzymes may play early role in cancer
7. HWI scientist first in world to unravel structure of key breast cancer target enzyme
8. Researchers first to see reactive oxygen species in vital enzyme
9. Disabling enzyme allows mice to gorge without becoming obese, new study finds
10. Structure of enzyme against chemical warfare agents determined
11. Researchers find pathway and enzyme unique to tularemia organism
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/16/2017)... , Feb. 16, 2017  Genos, a community ... that it has received Laboratory Accreditation from the ... is presented to laboratories that meet stringent requirements ... scientifically rigorous processes. "Genos is committed ... laboratory practices. We,re honored to be receiving CAP ...
(Date:2/13/2017)... -- Former 9/11 Commission border counsel and Special Counsel ... of Identity Strategy Partners, LLP, today releases the ... Order: Protecting the Nation From Foreign Terrorist Entry Into ... President Trump,s ,Travel Ban, Executive Order gains more notoriety ... travel ban, it is important that our national discourse ...
(Date:2/8/2017)... About Voice Recognition Biometrics Voice recognition biometrics ... a stored voiceprint template. Acoustic features of an ... are compared to distinguish between individual voices. Voice ... PCs already have a microphone and can authenticate ... are most likely to be deployed in telephone-based ...
Breaking Biology News(10 mins):
(Date:2/23/2017)...  Imanis Life Sciences announced today the launch ... viruses for virotherapy research. These viruses are licensed ... vaccinia virus-based technology platform for research use. ... partnership with Genelux to offer researchers, for the ... in research," said Dr. Kah Whye Peng ...
(Date:2/23/2017)... ... ... Today, researchers can fast-track sample collection and analysis for ... or SNPs of interest) using one, easy-to-collect saliva sample. With the addition of ... and other relevant biomarkers can be extensively studied through a non-invasive sample type. ...
(Date:2/23/2017)... and SAN FRANCISCO , Feb. ... regenerative medicine company, and Beyond Type 1, a not-for-profit ... 1 diabetes, today announced a grant from Beyond Type ... cure for type 1 and other insulin-requiring diabetes.  ... been developing innovative stem cell-derived cell replacement therapies with ...
(Date:2/22/2017)... ... February 22, 2017 , ... Park Systems , a leader in Atomic ... all SPIE attendees and Park customers on Feb. 27, 2017 from 12-2pm ... Jose Convention Center. The luncheon will feature a talk on Automated AFM for ...
Breaking Biology Technology: