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All Hans Kiefer wants is pure proteins

Hans Kiefer has been involved with the purification of proteins since he first became a biochemist in the 1990s. While his early research at the Max Planck Institute of Biology focused on theoretical research aspects, the 47-year-old is now investigating therapeutic proteins. Kiefer has been professor of protein purification and protein analytics at the Biberach University of Applied Sciences since September 2007.

Prof. Dr. Hans Kiefer. © Biberach University

Shortly after he settled at the Biberach University of Applied Sciences, Kiefer bagged a successful grant application. The grant from the German Federal Ministry of Education and Research laid the foundation stone for the future research project of the young Institute of Pharmaceutical Biotechnology.

The goal of the project, which also involves three pharmaceutical companies and the University of Karlsruhe, is to develop a method that enables the cheaper purification of therapeutic proteins with the intention of replacing chromatographic protein separation. Kiefer's approach is aimed at purifying pharmaceutical proteins by way of crystallisation.

After obtaining his biochemistry degree, Kiefer received his PhD from the Max Planck Institute of Biology in Tübingen on the structure and movements of a membrane protein. His work in the biophysics MPI group involved the purification of proteins, and Kiefer has been thrilled by these sophisticated, water insoluble membrane proteins ever since. He used a well-known E. coli protein to gain insights into how a transport protein manages to transport molecules across the cell membrane.

 

Erroneous folding

At the beginning of the 1990s, Kiefer’s supervisor introduced him to G-protein coupled receptors, a class of proteins that had just been discovered. G-protein coupled receptors are found in human cells, they mediate signals and have a decisive influence on the effect of around one in two drugs. Kiefer went to Hohenheim where he worked with olfactory receptors, which are the largest group of G-protein coupled receptors, and where he also learned to successfully apply molecular biology methods. When bacteria are engineered to produce human membrane proteins, these proteins are not integrated into the membrane, but deposited in the cell’s interior where they form aggregates in which the proteins are not properly folded, explained Kiefer.

Towards pharmacologically interesting proteins

Protein crystal of the pharmacologically interesting malic enzyme. © NASA

This brought the biochemist into contact with another closely related topic: the folding of proteins. It is difficult, though not impossible, to make proteins refold correctly. At the time, folding was already known to work for soluble proteins in a suitable environment. However, the correct folding of membrane proteins required a different technique and Kiefer took several years to come up with a suitable solution.

After only 12 months at the University of Hohenheim, Kiefer went on to work at the Karolinska Institute and the University of Stockholm in Sweden, where he spent his postdoctoral period investigating the conditions under which proteins are channelled through the membrane.

In 1996, he returned to Hohenheim to become head of his own research group, at which point he abandoned his work with olfactory receptors and turned his attention to pharmacologically interesting proteins.

One particular contact changed (almost) everything

Kiefer spent four years at the University of Hohenheim, where he carried out research and published his results. The protein specialist recalls that a Swedish pharmaceutical company contacted him at one stage, offering him money for the production of receptors. Kiefer used the money to buy a computer and pay the wages of his doctoral students. Eventually – in the era when biotechnology was booming and venture capital was easily available – Hans Kiefer and two partners decided to establish their own company.

Crystallisation instead of the clarification of structures

Lysozyme crystal © Mathias Klode

However, Kiefer's business career came to an end six years after the establishment of the company. He has stayed in contact with the company that took over his business, for which he provides consulting services. When the biotech bubble eventually burst, the long-term goal to sell protein structures to pharmaceutical companies was no longer possible.

At the Biberach University of Applied Sciences, where he has been professor of protein biochemistry and biotechnological purification since 1st September 2007, Kiefer has shifted his research priorities from protein structure to protein crystallisation. He also enjoys teaching, which means that the return to academia suits him perfectly.

Chromatography is far too expensive

Biopharmaceutical production at Boehringer Ingelheim's Biberach/Riss company site. © Boehringer Ingelheim

Together with colleagues at the University of Karlsruhe, Kiefer is now focusing on a problem the biopharmaceutical industry is at pains to solve. The purification (process engineers call this process downstream processing) of recombinant therapeutic proteins from the fermentation broth is very expensive, amounting to around 90 percent of entire production costs. 

In view of expiring patents and biosimilars that can be produced cost-efficiently with state-of-the-art cell culture technologies, the manufacturers of therapeutic proteins are looking for ways to make their production more economical. Kiefer believes that chromatographic separation will most likely also be used to process proteins in the future, but envisages that it will be possible to at least replace part of the chromatographic separation through crystallisation, which is considerably cheaper.

Hope for very high purity

Kiefer is convinced that crystallisation has several advantages: it does not require expensive chromatographic material and the proteins assemble spontaneously to form a crystal, giving them a very regular structure. This makes them very stable and the regular structure ensures that no protein contaminations occur in the crystal, making crystallisation an excellent method of purification. Kiefer also hopes that crystallisation will lead to a high protein purity.

Kiefer and his partners are hoping to start their three-year project in the very near future. The proteins have already been obtained from three pharmaceutical companies. The crystallisation conditions of the proteins will be investigated systematically at laboratory scale in Biberach before being transferred to Karlsruhe and to a scale (10 gr) which will enable industrial implementation.

Still fascinated by the wonders of nature

Protein crystal of the factor D enzyme © NASA

Although Kiefer's research has become more application-oriented than in his early years, he has still not lost his enthusiasm for his particular area of expertise. The scientist is still fascinated by how a protein consisting of about 20,000 molecules assembles almost magically into a crystal.

Nevertheless, after more than ten years of active research, Hans Kiefer no longer dreams of achieving what he once hoped to achieve. He is now not so convinced that he will be able to clarify the three-dimensional structure of a receptor. He has learned a lot about the imponderability of his field of research. The protein expert is now setting himself more realistic goals. And if he and his colleagues succeed in establishing the young Biberach institute as a research institute for biopharmaceutical manufacturing processes, then the biochemist Hans Kiefer will certainly be happy with his work and achievements.

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