Researchers flexed their intellectual muscles at a Royal Society meeting in
May to discuss the latest developments of our understanding of the diverse
functions of myosin and its role in muscle and motility.
The protein myosin forms the bulk of our muscles. Muscle fibres themselves
are made up of bundles of smaller myofibrils, which in turn are composed of
units known as sarcomeres. Myosin forms thick filaments interspersed with
thin filaments made of a second protein, actin. When a muscle contracts the
two sets of filaments slide past each other - a discovery made just fifty
years ago and celebrated at the RS meeting.
Since the discovery of the sliding filaments the big question has been: what
makes them slide? It turns out that the myosin filaments have appendages
known as crossbridges that can cyclically interact with the actin filaments
moving them along by a kind of rowing action. The fuel for this process is
provided by the breakdown (hydrolysis) of the chemical adenosine
triphosphate (ATP), which is the body's energy molecule obtained from the
breakdown of sugar.
The myosin crossbridge is the enzyme that hydrolyses ATP to adenosine
diphosphate (ADP) and efficiently converts chemical energy into mechanical
work. Scientists are now close to understanding the myosin crossbridge in
atomic terms as a molecular machine, a wonderful natural example of
nanotechnology.
The story of myosin does not, however, stop there. Myosins are also involved
in many processes in the cell involving motility, such as the absorption of
nutrients, the transport and release of signalling chemicals by nerve cells
and even play a crucial role in hearing. Whether you are flexing your biceps
or listening to Puccini, myosins are involved.
Part 2 -
Mechanism of muscle contraction
Check this article to find out about creatine and muscle growth