Could you explain the research that your team conducts?
We deal with the recognition of the biochemical mechanisms responsible for the synthesis of complexes made up of atoms of iron and sulphur known as iron-sulphur clusters. They are vital to the functioning of many proteins in every living cell. As we know, protein is responsible for all life processes: the reproduction of DNA, growth and cell division and energy transformation. If we compare protein to a machine with a certain function, then the iron-sulphur clusters can be compared to the universal components essential to its operation. Over 200 different proteins have been identified that contain the clusters we’re investigating. For a long time it was believed that these iron-sulphur clusters were generated spontaneously. It was only towards the end of the 1990s that it was discovered that their synthesis, as with other cell processes, requires the participation of many specialised proteins.
Our aim is to identify these proteins, to recognise the genes that code them and to describe the mechanism of how they function. It’s like analysing the elements and operating principles of a complicated machine when all we know is that it produces iron-sulphur clusters for the benefit of cell proteins. We do not know which components it consists of, how they are interconnected or how the production process works.
Iron-sulphur clusters are present in all cells – in bacteria, fungi, plants and animals. In humans, mutations in the genes which code protein occurring in the process of their synthesis cause genetically determined disorders. The most frequent disorder is Friedreich's ataxia. We know both the gene and the mutation that cause this condition but we still do not know the function of the protein it codes.
In our latest publication we showed how frataxin, the protein responsible for Friedreich’s ataxia, interacts with other proteins responsible for the synthesis of iron-sulphur clusters. What that means is that we purified the protein in question and demonstrated in a test-tube that it creates a complex. Next, using computer methods and the published structures of these proteins, we forecast the architecture of this complex, i.e. which structural elements are responsible for the mutual interaction in these proteins. You could compare it to solving a 3D jigsaw puzzle. Afterwards, we verified our forecast concerning the biochemical mechanism behind this complex by introducing changes in the structure of the protein with the aid of genetic engineering technology that inhibits mutual interaction. Finally, we introduced genes which code mutated protein into living cells, which resulted in the disruption of their mutual interaction, thereby confirming that the mechanism we had discovered does in fact function in yeast cells.
Why was yeast chosen, if the cells are so distant in terms of evolution from human cells?
That is true. But the research I have just described would be very difficult to conduct on humans. Luckily, the process of iron-sulphur cluster synthesis is very conservative and has not changed through the evolution from bacteria to human. For example, you could replace the genes which code those proteins active in the synthesis of iron-sulphur clusters in yeast cells, such as those used to make bread and beer, with their human counterparts and the yeast would live and thrive. This is very helpful in research. Yeast is our favourite research model.
The mechanisms responsible for the evolution of proteins are at the centre of our attention. We have for instance demonstrated that although the majority of proteins active in the synthesis of iron-sulphur clusters are inherited from bacterial predecessors, in the case of one, called Hsp70, the evolutionary history is much more complicated. In cells like ours which contain a cell nucleus there is no equivalent for the bacterial gene Hsp70 which specialised in the synthesis of iron-sulphur clusters. This function has been assumed by a different gene which, apart from participating in the synthesis of iron-sulphur clusters, also fulfils other important roles such as transporting protein through the cell membranes and protecting them from stress factors such as high temperature. This discovery showed that in the process of evolution some proteins can be replaced by others and the decisive factor is natural selection as much as a coincidence. The history of Hsp70 doesn’t end there. The most interesting discovery of my career so far was showing that at the late stage in the evolution of yeast there was a duplication in the gene which codes the multifunctional Hsp70 and that the newly-formed copy became specialised in the course of its evolution and is now active exclusively in the process of the synthesis of iron-sulphur clusters. So evolution has gone full circle. Firstly we had the Hsp70 gene in bacteria, specialising in the process of the synthesis of clusters, then with the advent of the cell nuclei this gene was lost and its role assumed by another gene coding multi-functional protein so that the duplicated copy of this gene again underwent specialisation in the predecessor of baker’s yeast.
In the process of evolution the proteins which fulfil these new functions come about as the result of the duplication of existing genes. So our research has cast new light not only on the process of the synthesis of iron-sulphur clusters but also on the evolutionary mechanism responsible for the creation of new proteins. Now we are trying to answer the question as to which changes in the sequence and structure of the Hsp70 protein allowed it to specialise again and what the functional consequences of the formation of a specialised protein are.
For many people, the sphere of genes, proteins and evolution is all black magic. Where does your interest stem from?
I studied Biology at the University of Gdańsk. The choice of course was not a difficult one. As long as I can remember I have been fascinated with biology and after winning a Biology Competition, I got in without any exams. During my studies, I kept up my interest in the animal kingdom and I wrote my MA thesis in the Department of Vertebrate Ecology. But towards the end of my studies I started to get interested in biochemistry. I remember one sentence from a lecture with Professor Karol Taylor: “biologists ask the questions and biochemists answer them”, which means that biochemical mechanisms lie at the heart of all life processes.
My doctorate in Biochemistry was done at Gdańsk Medical University’s Department of Biochemistry on the mechanical functions of the enzymes responsible for nitrogen compound metabolism in mammals and birds. There I learnt the ins and outs of biochemistry but I also realised that biochemistry cannot answer the key questions concerning adaption and evolution without genetics.
Right after my doctorate, I returned to my alma mater and the Department of Molecular Biology. I had intended to combine biochemistry with molecular biology and genetics but I didn’t know what I wanted to research. I was lucky because Professor Maciej Żylicz was researching the newly-discovered Hsp70 proteins. I was intrigued by their role in the replication of DNA and this is what I dedicated myself to for the next few years during internships in Michigan State University with Professor Jon Kaguni and later at the Ludwig Maximilian University of Munich with Professor Walter Neupert. Initially I researched the role of Hsp70 in the replication of DNA in bacteria and bacterial viruses and later in the replication of the mitochondrial DNA of yeast.
The replication of DNA is one of the most basic biological processes.
That’s correct. Everyone knows that the replication of DNA is important and learning how it works allows us to understand the key biological processes and the causes of many diseases. Cancer, for example, since cancer cells are those in which the process of replication of DNA has been disrupted. However, the very fact that the replication process is that important makes it a difficult subject to research and the ‘lowest hanging fruit’ has already been picked by generations of researchers in the area. The competition is enormous and you really have to be very inventive to make your name in such a crowded field of research. I know because I was convinced when I published the results of research on the replication of mitochondrial DNA. Luckily in 1999 when I was on an academic internship at Wisconsin State University in Madison with Professor Elizabeth Craig, it turned out that the newly discovered variant of the mitochondrial protein Hsp70 we were investigating is not present, despite what we had expected, in the replication of DNA but only in the newly discovered process of the synthesis of iron-sulphur clusters.
On the subject of young researchers, what would be your main advice to those just starting out on their careers?
Above all, I am convinced that the master-pupil relationship is the basis of a good start to your career. We learn how to work in science from others and it’s best if those we learn from are good scientists, since we do not only learn what is worth researching but we also meet other scientists working in our field of research. These links may prove the key to the future stages of our career, doctorate, post-doctoral internship and starting up our own research group. As to the subject of research, as I mentioned, you can’t give in to the fashion and follow the universally familiar problems such as an effective therapy against HIV or a cure for cancer. There are already thousands of researchers working on these important but obvious issues and it would be difficult to compete. At the same time, the biochemical and molecular foundations of the life processes are common to cancer cells and other types of cell. Sometimes research into a newly discovered metabolic or regulatory process can cast light on apparently far-removed issues. We are unable to predict this but the history of science is full of such unexpected plot twists.
Young scientists need a master but they also need fields which are interesting and little explored. How do you recognise them?
Despite appearances, the product of a scientist’s work is well defined. It is publication in an academic journal. And the quality of the publication is to a large extent measurable. It’s calculated by the number of citations by other scientists and the prestige of the journal in which it appeared. If you’re looking for a master, analyse the candidate’s publications. Make sure that the works are current and not from the distant past, since science changes very dynamically. The success of a scientist depends on engagement in the work and concentration and at the same time, maintaining a wider perspective. Do not waste opportunities that come along. Allow the subject of your research, for example the protein you are characterising, to take you into new, as yet unknown, processes. Don’t be afraid to change your subject of research if the change is the logical consequence of the results you attained.
What is your life like outside science? Do you have a hobby?
Of course. I believe that the ability to relax after work is just as important as concentrating while at work. I am an active person and maybe even hyperactive. So my hobbies are various activities in the open air – riding a bike (racing and mountain), sea kayaking and roller-skating, but also walking in the forest combined with observing birds and animals. In these activities I am accompanied by my wife. I’m lucky because we have very similar interests. We listen to music and watch films together. And we take our dachshund for a walk together. My wife is not a scientist but she’s interested in science and reads Świat Nauki regularly. I often discuss the latest results and ideas with her, which allows me to maintain a fresh outlook and a broader perspective.
Interview: Krzysztof Klinkosz
Photography: Piotr Pędziszewski