Scientists at the European Molecular Biology Laboratory (EMBL) in Hamburg, Germany, have discovered that the elastic part of the protein myomesin can stretch to two and a half times its original length, unfolding in a way that was up to now unknown.
In muscle, the stretchy tails of two myomesin molecules come together, forming an elastic bridge that keeps a bundle of muscle fibres together. Each tail looks like a set of pearls - called immunoglobulin-like domains (pink, blue) - spaced out along an elastic band of structures known as alpha helices (green). When the protein is pulled, as it is when muscles contract and extend, the helices unfold.
To obtain this unprecedentedly detailed view of myomesin's three-dimensional structure and discover the secret behind its stretchiness, the scientists combined an array of techniques: X-ray crystallography, small angle X-ray scattering, electron microscopy and atomic force microscopy.
Statement of Matthias Wilmanns, Head of EMBL Hamburg
"Next, we would like to determine the structure of the complete myomesin filament, and to find out about the protein's function in living organisms, starting with animal models."
A video of stretching myomesin can be seen here
The work, published today in PLoS Biology, was conducted in collaboration with scientists from the Technical University of Munich, in Germany, and The Institute of Cancer Research, in the UK.
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Keywords: AFM Atomic force microscopy biology Biology Research Chatziefthimiou DESY Electron Microscopy European Molecular Biology Laboratory (EMBL) Filaments Institute of Cancer Research Life Science Matthias Wilmanns Muscle Myomesin Myosin Pinotsis PLoS Biology Technical University of Munich X-Ray X-ray Crystallography X-ray scattering