Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Image of myosin-actin interaction revealed in cover story of Molecular Cell

30.09.2005


3-Dimensional Imaging of Motor Proteins Provides New Insights to Molecular Mechanics of Cell Motility, Muscle Contraction



Scientists from the Burnham Institute for Medical Research and the University of Vermont have captured the first 3-dimensional (3D) atomic-resolution images of the motor protein myosin V as it "walks" along other proteins, revealing new structural insights that advance the current model of protein motility and muscle contraction. The culmination of four years of work, this collaboration among biochemists and structural biologists was selected as the cover story for the September issue of the scientific journal Molecular Cell.

The Burnham team, led by Dorit Hanein, Ph.D., was the first to reveal the 3D representation of myosin V "walking" along actin filament, a key protein involved in motility and muscle contraction. Using electron-cryo microscopy to take 3D snapshots of myosin V and actin interacting, researchers were able to see myosin V moving along the actin substrate in a "natural state." Previous 2D models have been based on staining or other treatment of the myosin that might alter the complex’s natural mechanism of action.


Myosins are a large family of motor proteins that interact with actin filaments for motor movement and muscle contraction. Myosin V is the workhorse of the myosin protein family. It exists to ferry a cargo of proteins needed in a specific place at a specific time. Fueled by hydrolysis -- the process of converting the molecule adenosine triphosphate (ATP) into energy -- myosin V travels in one direction using actin as a track to deliver its payload of cell vesicles and organelles. Myosin V is also involved in transporting proteins that signal and communicate with other cells.

Myosin V has a two-chained "tail" that diverges to form two "heads" that bind to specific grooves on actin and walk hand over hand along the track, similar to the way a child moves along the monkey bars in a playground. Myosin V differs from the other myosin family proteins in that it is able to sustain this processive motion, enduring many hydrolysis cycles. The other myosins grab on tightly to actin and release after one hydrolysis cycle.

"This study required a different way of thinking about image analysis. This is the first time we were able to structurally visualize the weak binding states of actin and myosin, not interpolated from crystal structures, and not interpolated from biophysical methods," said Dr. Hanein. "We were able to see structural changes in the myosin lever arm as well as in the actin interface as it propagates through the hydrolysis cycle."

Structural information from previous studies provided information about parts of this process, but until the present collaboration, visualizing Myosin V in its weakly bound state to actin had not been possible. The Hanein group captured snapshots of Myosin V at several points during a hydrolysis cycle. Their use of electron cryo-microscopy made it possible to visualize flexible structural domains, which tether the Myosin V, helping to keep the protein on its actin track through the weak binding phase of the processive movement.

The detailed molecular knowledge of how myosin interacts through the hydrolysis cycle with actin provides an exciting new research template onto which scientists can design new sets of experiments to further refine the myosin-actin binding region and to correlate it with loss or gain of function. The precise characterization of this myosin-actin interface is critical, evident by the way a single amino acid change in myosin leads to familial hypertrophic cardiomyopathy (FHC), an undetectable condition resulting in death by sudden cardiac arrest in otherwise healthy young adults.

Contributors to this work include: Niels Volkmann, Ph.D., assistant professor and first author on this publication, Dorit Hanein, Ph.D., associate professor, Hong-Jun Liu and Larnele Hazelwood from the Burnham Institute for Medical Research; and Kathleen M. Trybus, Ph.D., Susan Lowey, Ph.D., and Elena B. Kremenstova, Ph.D., from the Department of Molecular Physiology and Biophysics at the University of Vermont.

Functional, biochemical assays were conducted by collaborators from the University of Vermont, directed by Kathleen Trybus, Ph.D.

Nancy Beddingfield | EurekAlert!
Further information:
http://www.burnham.org

More articles from Life Sciences:

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

nachricht Pollen taxi for bacteria
18.07.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>