Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Peering into cell structures where neurodiseases emerge

26.11.2015

PeeriMagic-angle-spinning NMR used to probe protein/microtubule assembly at atomic scale

A latticework of tiny tubes called microtubules gives your cells their shape and also acts like a railroad track that essential proteins travel on. But if there is a glitch in the connection between train and track, diseases can occur.


The CAP-Gly protein (shown in lavender) is docked onto microtubules. This zoom-in also shows the interaction interface.

Credit: Polenova Lab/University of Delaware

In the Proceedings of the National Academy of Sciences, Tatyana Polenova, professor of chemistry and biochemistry, and her team at the University of Delaware, together with John C. Williams, associate professor at the Beckman Research Institute of City of Hope in Duarte, California, reveal for the first time -- atom by atom -- the structure of one of these proteins bound to a microtubule.

The protein of focus, CAP-Gly, short for "cytoskeleton-associated protein-glycine-rich domains," is a component of dynactin, which binds with the motor protein dynein to move cargoes of essential proteins along the microtubule tracks. Mutations in CAP-Gly have been linked to such neurological diseases and disorders as Perry syndrome and distal spinal bulbar muscular dystrophy.

The research team used magic-angle-spinning nuclear magnetic resonance spectrometry (NMR) in the Department of Chemistry and Biochemistry at UD to unveil the structure of the CAP-Gly protein assembled on polymerized microtubules. The CAP-Gly protein has 1,329 atoms, and each tubulin dimer, which is a building block for microtubules, has nearly 14,000 atoms.

"This is the first time anyone has been able to get an atomic-resolution structure of any microtubule-associated protein assembled on polymerized microtubules," Polenova says. "With magic-angle-spinning NMR, we can look into the structure of this and other assemblies of microtubules and their associated proteins and gain critical insights into their function and dynamics, as well as begin to gather clues as to how mutations cause disease."

In this technique, a sample is placed in the NMR's small, tube-like rotor, which is then spun inside the NMR magnet at an angle of 54.74 degrees -- called the "magic angle" because it suppresses the atoms from interacting magnetically.

The result is a high-resolution protein fingerprint, a graph of hundreds of peaks representing the frequencies of two or more interacting atoms. These data are then used to calculate the 3-D structures.

The 3-D structures of CAP-Gly, which show the spatial arrangement of atoms in the protein molecule, are different between the free state of the protein and its bound state to the microtubule. These structures reveal how the protein interacts with microtubules, predominantly through its loop regions, which adopt specific conformations upon binding.

However, static structures of CAP-Gly do not tell the whole story about the protein.

"Just as we are always moving our arms and legs about, proteins are very dynamic. They do not stand still," Polenova says. "These motions are essential to their biological function, and NMR spectroscopy is the only technique that can record such movements, with atomic resolution, on a variety of time scales, from picoseconds to arbitrarily long time scales -- seconds, days, weeks -- to help us understand the protein's function. We know from our prior studies that CAP-Gly is dynamic on timescales from nano- to milliseconds, and this mobility is essential for the protein's ability to interact with microtubules and with multiple other binding partners."

The research, which has been ongoing since 2008 when the first data sets were collected, required the development of new protocols for preparing the samples, new NMR experiments to gather various information on structure and dynamics, and new protocols for data analysis.

In the future, Polenova and her team envision using NMR in combination with cryo-electron microscopy, in which samples are studied at extremely low temperatures, typically below 200 degrees Fahrenheit, to look at even more complex systems in a highly preserved form.

###

Polenova's research team at UD included Si Yan, who received her doctorate from the University in 2014, current doctoral student Changmiao Guo, NMR spectroscopist Guangjin Hou and postdoctoral researchers Huilan Zhang and Xingyu Lu. Williams, at Beckman Research Institute, also was a co-author of the study.

The research was supported by the National Institutes of Health through a grant from the National Institute of General Medical Sciences. The National Science Foundation funded one of the NMR spectrometers used in the research.

Peter Bothum | EurekAlert!

Further reports about: 3-D structures cell structures diseases microtubule microtubules proteins structures

More articles from Life Sciences:

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

nachricht Antimicrobial substances identified in Komodo dragon blood
23.02.2017 | American Chemical Society

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

NASA eyes Pineapple Express soaking California

24.02.2017 | Earth Sciences

New gene for atrazine resistance identified in waterhemp

24.02.2017 | Agricultural and Forestry Science

New Mechanisms of Gene Inactivation may prevent Aging and Cancer

24.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>