�Understanding the form and function of certain proteins in the human physical structure is becoming faster and easier, thanks to the work of researchers at the University of Illinois.
By combining custom-built spectrometers, novel probe designs and faster pulse sequences, a squad led by Illinois chemistry professor Chad Rienstra has developed unique capabilities for probing protein chemistry and structure through the manipulation of solid-state nuclear magnetic resonance spectroscopy.
The researchers' recent results represent significant advancement toward atomic-scale resolution of protein structure by solid-state NMR spectrometry. The technique can be applied to a large range of membrane proteins and fibrils, which, because they ar not water-soluble, are a great deal not amenable to more than conventional solution NMR spectrographic analysis or X-ray crystallography.
"In our experiments, we explore couplings between atoms in proteins," Rienstra aforesaid. "Our goal is to translate genomic information into high-resolution structural information, and thereby be able to better empathise the function of the proteins."
Solid-state NMR spectroscopy relaxes the need for solvability of the sample. In solution NMR spectroscopy, molecules are allowed to tumble randomly in the charismatic field. In solid-state NMR spectroscopy, molecules are immobilized within a small cylinder called a rotor. The rotor is then spun at high speed in the magnetic field.
"With increased speed and sensitivity, we can get very heights resolution spectra," Rienstra said. "And, because we commode resolve thousands of signals at a time - one for each atom in the sample - we can buoy determine the structure of the intact protein."
To amend sensitivity and accelerate information collection, Rienstra's group is developing smaller rotors that can be spun at rates surpassing 25,000 rotations per second. The faster rotation rate and smaller sample size allows the researchers to hold more data in less time, and solve structure with just a few milligrams of protein.
The determination of protein structure benefits not only from improvements in engineering, but too from the researchers' novel approach to refining geometric parameters.
Structure determination is ordinarily based upon distances between atoms. Rienstra discovered a way of measuring both the distance between atoms and their relative orientations with very high precision.
"Using this technique, we pot more exactly define the fragments of the particle, and how they ar oriented," Rienstra said. "That allows us to delineate protein features and ascertain structure at the atomic scale."
Rienstra will describe his group's modish findings and techniques at the home meeting of the American Chemical Society, to be held in Philadelphia, Aug. 17-21. Rienstra and his collaborators described their work - creating the highest resolution protein structure resolved by solid-state NMR - in the March 25 issue of the Proceedings of the National Academy of Sciences.
The work was funded by the National Science Foundation and the National Institutes of Health.
Source: James E. Kloeppel
University of Illinois at Urbana-Champaign
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