Proteins – the building blocks of life

Proteins – the building blocks of life

To say that Marjolein Thunnissen has been interested in structural biology and synchrotron research since early childhood would be an exaggeration, but only a slight one. Marjolein was actually only 19 when she knew this was what she wanted to focus on. The overall objective of her work is to gain more knowledge about proteins, the building blocks of life.

Marjolein Thunnissen is a chemist from the Netherlands. It was at the end of her first year as a chemistry student that she took a course on protein structure – a course that was to be decisive for her future.

“I thought that it was so incredibly interesting! Even then I knew that this was the direction I wanted to take”, she says.

Structural biology can be described as a field of science that concerns the physical structure of large molecules – macromolecules. The most important of these are the proteins, those molecules that do most of the work within all living bodies.

In the human body, for example, it is the protein alpha keratin that gives rise to our hair and our nails; the protein haemoglobin that enables the blood’s oxygen to reach all the cells in the body; the muscle proteins actin and myosin that facilitate all large and small muscle movements, and so on.

The proteins often function as enzymes that accelerate various chemical reactions. However, they also have many other tasks, such as being a part of the immune system, storing different substances, and acting as messengers between cells. The human body has only about 25,000 genes, but the number of proteins that genes give rise to is far greater –­ close to 250,000.

All proteins are shaped like long necklaces with pearls made up of different amino acids. However, the necklace is crinkled in various ways, often with alternating straight and “curly” sections. It is this crinkling that constitutes the protein structure, which is decisive for the protein’s function.

“To understand why different things happen in the body, you must look at the protein’s shape. Structural biology is the best tool we have for doing this. The most recent medical findings concerning the understanding and treatment of different diseases are very often based on what has been learned about the proteins’ structure“, explains Marjolein Thunnissen.

When she was a young student studying chemistry in Groningen, her teacher asked if she would like to come along on a trip to a synchrotron radiation facility in Germany. She definitely wanted to.

Synchrotron radiation facilities, which use an extremely fast and focused X-ray beam, were mostly used at that time for technical materials research and relatively little in biological contexts. The study of protein structures is still just one of the many areas in which synchrotron radiation can be used, but it is an important one.

During structural biological studies, the X-ray beams from the synchrotron focus on a crystallised molecule. The way the beams are reflected by the crystal gives a hint of what the molecule’s structure looks like. Rotating the crystal and using different wavelengths of radiation enables the collection of data that gradually provides a picture of the molecule’s shape.

After her education in the Netherlands, and before Marjolein Thunnissen started at MAX Lab in Lund, she worked on protein crystallography at Stockholm University. This involves the extraction of small drops from a liquid solution, which are then concentrated step by step until a crystal is grown.

Making crystals from a protein can be easy or difficult, depending on the protein in question. The work can take several months, and requires that temperature, acidity and concentration are adapted exactly to each protein. The result, if all goes well, is a crystal that is barely visible to the naked eye, but contains trillions of molecules.

In Stockholm, Marjolein Thunnissen also worked on the analysis of data from protein crystals that were sent away for investigation to various synchrotrons. She continued performing such analyses at MAX Lab, where she has also been involved in instrumentation and method development. She has never regretted moving to Lund.

“I had known about, and been interested in, the research at MAX Lab for a long time. The quality of the data is incredibly important in determining the structure of a molecule and the beamline at MAX Lab delivers high quality. This ensures a good result”, she says.

She also appreciates that the work is so varied, as so many professional groups are involved. In a single day she can meet technicians, physicists, chemists, biologists and doctors. She can also get to do some of the practical work.

“Of course we have technical specialists at MAX Lab, but sometimes I can get the chance to do the hands-on work myself, and I think that’s a lot of fun!” she says.

She also thinks it is fun to talk about MAX Lab when there are external visitors such as schoolchildren. Explaining such advanced technology to young people can appear to be a tough challenge, but it usually goes well, she observes.

“They are always impressed when they see the sheer size of our apparatus. And, of course, we have also been involved in many projects that are both exciting and comprehensible, like studies of the 17th century warship Vasa, and of fossilised feathers and dinosaur bones. And the value of studies that can provide new drugs, batteries with a longer life, materials that conduct electricity better, more efficient solar cells and so on is also easy to understand.”

The list of research publications that Marjolein Thunnissen has been involved in spans a wide field, from influenza bacteria to fibre proteins in arthritis and the small protein, WT1, which is significant in childhood cancer. These are studies that have been run by other researchers, in which she has contributed the synchrotron-related work. Her own research has been about leukotrienes, a family of hormones that play an important role in inflammation and are present in high concentrations among people with rheumatic diseases.

However, she will now have to put her own research to one side, as she has new duties at MAX IV. She will not have responsibility for just one beamline, as at MAX Lab, but coordinate activities for several beamlines. The new facility will provide completely new opportunities, not least in structural biology.

“We will have an extremely focused and intense beam, which will help us do things that have never been done before. Previously, we have followed developments elsewhere, but now it will be Lund that takes the lead. It will be a totally new situation and a real challenge”, she states.

In the private sphere, Marjolein Thunnissen is married – her husband is also a structural biologist at Lund University – and has two daughters and several cats. One of her main leisure interests is knitting. She has published no less than 13 of her own designs for sweaters, hats and children’s clothes on the international knitting site, Ravelry.

She thinks that working with her hands is a good change from research, although there are certain similarities between structural biology and knitting:

“Well, mathematics is involved in both activities, and both concern trying to grasp a three-dimensional shape!”

Story by: INGELA BJÖRCK

Photo: Kennet Ruona.