Myoglobin: A brief history of structural biology

The world's first glimpse at protein structure

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A scientific revolution

In 1958 John Kendrew unveiled the first protein structure ever to be seen by humankind, a true milestone in the history of structural biology. That protein was Myoglobin a vital factor in the biochemical reactions that fuel our everyday activities.

Professor Stephen Curry explains how the method they used to determine its structure, X-ray crystallography, has revolutionised the way that we study biology. In the case of myoglobin it revealed how this protein functions and, when compared to the similarly structured haemoglobin molecule, unveiled more about the evolutionary relationship between different species.

Since this landmark achievement over 90,000 structures of protein, DNA and RNA molecules have been determined using X-ray crystallography, providing valuable insights into the molecular-level workings of life.

Special thanks to the Science Museum for letting us film with their model. This film originally appeared in the Ri Chromosome series supported by BBSRC.

The Crystallography Collection is supported by the Science and Technology Facilities Council.

Themes

Being Human, Talking Science

Details

Type:
Demo
Organisations/Partners:
STFC
People:
Professor Stephen Curry
Location:
London, UK
Published:
2013
Filmed:
2013
Credits:

Ed Prosser / The Royal Institution

Collections with this video:
The Crystallography Collection

cc_by-nc-sa License: Creative Commons

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Transcript

[MUSIC AND FIREWORKS]

Exercise, love it or hate it, we've all got to do it. And it's thanks to a protein called myoglobin that we can extract oxygen from our red blood cells and store it in our muscles. Encoded by a gene on chromosome 22, myoglobin has a key role in providing oxygen for the biochemical reactions that keep us moving. But the protein also has a very significant place in the history of 20th century science. And it all started with this.

Here at the Science Museum in London is an early model of the myoglobin molecule. And while it may not look very impressive, indeed the model is rather disgusting, it represents a landmark achievement. This, the culmination of over 20 years work by scientists working in Britain, is the very first protein structure to have been seen by humankind.

The model was built in 1958 by John Kendrew using information collected by firing x-rays at crystals of sperm whale myoglobin. By measuring the pattern of spots generated as the myoglobin crystals scattered the x-rays into many different directions, he was able to calculate the structure of the molecule. This early model is relatively crude. It only shows the overall shape of the protein.

But that's because Kendrew's first crystals weren't very good. But the technique, x-ray crystallography, would come to revolutionise the way that we study biology. And since 1958, it has allowed scientists to work out the structures of many different biological molecules, from the enzymes that digest our food to the ion channels that conduct electric signals in our brains.

Today, in my lab, we still use many of those same techniques that Kendrew first applied to myoglobin. Within a few years, he had improved his original crystals and was able to reveal the true complexity of myoglobin's atomic structure, unveiling its beautiful helices and the precise arrangement of bonds between its atoms. We can now see exactly how the protein chain folds around the porphyrin group to create a binding site for a single molecule of oxygen.

One of the most interesting things about this early work was that when Max Perutz applied crystallography to study horse haemoglobin, the molecule that transports oxygen in red blood cells, he could see for the first time that it was very similar in structure to myoglobin. This showed not just the evolutionary relationship at the molecular level between different species, horses and whales, but also that evolution could adapt a relatively simple structure and give it a more complex form and function.

In fact, if you take a glance to the right of Kendrew's model at the Science Museum, you'll see Max Perutz's structure of haemoglobin, which is made of four chains, each of which looks very like myoglobin. From that humble rather hideous start in 1958, it's amazing how far we've travelled. Over 90,000 structures of protein DNA and RNA molecules have now been determined by x-ray crystallography, giving us detailed insights into how life operates at the molecular level.

[MUSIC PLAYING]

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