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Biological Chemistry

Research Focus
General Facts
Research
Selected Publications
Selected Funding, Collaboration

Keywords: Structural biology, biomolecular crystallography, signal transduction/regulation, biochemistry, ether lipid metabolism, clinical chemistry, protein purification, high pressure liquid chromatography, bioethics, immunobiology
Research (ÖSTAT Classification): 106041, 301904, 301303, 301902, 302040

Research Focus

This unit studies the structural biology of disease proteins and is currently focusing on neurofibromatosis type 1, a hereditary disease that has a relatively high incidence but is poorly understood in respect of its pathogenic mechanisms. In addition, we investigate complexes that are important for endosomal functions. Furthermore, the research of this unit is directed towards understanding the biochemistry and clinical immunology of pteridine and tryptophan metabolism. Pteridines are structurally related to the vitamins folic acid and riboflavin but, in contrast to these, they are formed in the mammalian body and play a role in the metabolism of amino acids and ether lipids. In addition, we study ethical, cultural and social issues of novel technologies in biomedicine.

General Facts

The unit consists of six principal investigators, who study the impact of biomolecular systems on human health and disease. Our research areas include pteridine and lipid metabolism as well as intracellular signal transduction and its regulation, particularly in the context of (small) guanine nucleotide binding (G) proteins. In addition, we strive to understand novel biotechnologies in the context of biomedicine, how they are created and how they serve emerging markets. At the same time, we seek to explore their ethical, social and cultural dimensions. Based on research and education in this particular field, the inter-institutional and interdisciplinary bioethics network ethucation (http://www.i-med.ac.at/ethucation/index.html.en) was established in 2007 which is the Austrian unit of the UNESCO Chair in Bioethics’ (Haifa) International Network (http://www.unesco-chair-bioethics.org/).  The spectrum of our implemented methods includes biochemical techniques such as FPLC/HPLC for preparative protein purification and analysis, eukaryotic cell cultures, various biophysical as well as bioanalytical methods, and biomolecular x-ray crystallography. We consider teaching to be a major responsibility in the education of young scientists and we contribute to activities for students of the Medical University as well as Leopold-Franzens University, Innsbruck.

Research

Structural Biology: Structure and Interactions of the Neurofibromatosis Type1 Protein, Mechanisms of G-Protein Complexes
Klaus Scheffzek

We aim to understand the disease mechanisms of neurofibromatosis type 1 (NF1), a genetic disease with a relatively high incidence. NF1 patients have an increased risk of tumour, present a variety of developmental defects and frequently suffer from learning disabilities. Tumour-suppressor gene NF1 encodes the giant protein neurofibromin (320 kDa) and is not functional in NF1 patients, owing to genetic alterations. Our long-term goal is to define the functional spectrum of neurofibromin in as much detail as possible  Our research activities currently include determining the structure of neurofibromin (FWF grant: P28975) as well as defining its interacting partners (Dunzendorfer-Matt et al., 2016, PNAS 113, 7497 – 7502) (collaborations with Frank McCormick from UCSF and Lukas A. Huber in Innsbruck). In addition, we investigate the interactions between components of cellular complexes that are important for lysosomal function (collaboration with AG Huber; Araujo et al., 2017, Science 358, 377 – 381). We have continued to expand our platform of biophysical instruments by implementing a multi-angle light-scattering (MALS) system that is capable of accurately determining the molecular weight and levels of microheterogeneity of multicomponent complexes.

^{Fig. 1: Immunofluorescence image of LAMTOR components (red) and a lysosomal marker (LAMP1 in green, bottom right); the co-localisation of both components is shown in yellow. The crystal structure of the truncated Rag-Ragulator complex is shown as a zoom inset (top left). Here, the belt-like LAMTOR1 component is shown in red and the G-domains (position derived from structural alignments) are shown in grey (figure by A. Naschberger & MEG de Araujo, see de Araujo et al., Science 358 for scientific background).}

Neuropsychoimmunology
Dietmar Fuchs

Mood changes and depression are common in patients suffering from inflammatory disorders, such as viral infections, autoimmune syndromes, malignant tumour diseases and adiposity. Although the pathogenesis of these symptoms remains unclear, several of our recent studies have shown a correlation between neuropsychiatric deviations in patients and elevated concentrations of neopterin and increased tryptophan breakdown (Kyn/Trp) in blood samples. These findings shed light on the relevance and importance of the observations in neuropsychoimmunology and they appear to have special relevance in the course and for the outcome of disease associated with the coronavirus (COVID-19).

Higher blood phenylalanine levels and higher phenylalanine to tyrosine ratios have been observed in these patients as well as in healthy elderly patients. Combination of the Kyn/Trp ratio with the Phe/Tyr ratio can be especially helpful when deciding whether serotonergic or noradrenergic/adrenergic/dopaminergic treatments are more likely to be useful in the individual patient. More recently, the effect of nutrition and lifestyle (e.g. physical exercise and sport) on these aforementioned immunobiochemical pathways has been presented as a focal point of our research. In patients suffering from otherwise treatment-resistant depression, repetitive transcranial magnetic stimulation (rTMS) has some beneficial effect and it was observed that this is associated with a positive influence on phenylalanine metabolism, as shown in a collaboration with Kepler University in Linz.

Several clinical and in vitro studies using the model of freshly isolated peripheral blood mononuclear cells (PBMC) have been performed and more than 80 papers were published between 2017 and 2019 in a worldwide collaboration with different research groups.

Ether Lipid Metabolism: Novel Gene Assignments and Novel Research Tools
Katrin Watschinger, Gabriele Werner-Felmayer, Georg Golderer and Ernst R. Werner

Building on 40 years of pteridine research in the institute, we are currently focusing on ether lipid metabolism. The degradation of ether lipids requires alkylglycerol monooxygenase, an enzyme that is dependent on the cofactor tetrahydrobiopterin. Tetrahydrobiopterin is structurally related to the vitamins folic acid and riboflavin but is synthesised in the animal and human body. It is required for five specific hydroxylation reactions, which include the conversion of phenylalanine to tyrosine by phenylalanine hydroxylase, the key step in degradation of the essential amino acid phenylalanine. Tetrahydrobiopterin is currently used to treat phenylketonuria, a rare hereditary human disease that affects phenylalanine hydroxylase.

In 2010 we assigned a sequence to alkylglycerol monooxygenase, a tetrahydrobiopterin-dependent enzyme that metabolises ether lipids. For the first time, we established a functional connection between tetrahydrobiopterin and lipid metabolism in intact cells.

When it loses its function, fatty aldehyde dehydrogenase, the subsequent enzyme in ether lipid metabolism, causes a severe, rare, hereditary disease: Sjögren-Larrson Syndrome. We used biochemical and structural methods to characterise the human fatty aldehyde dehydrogenase and found that a special structural feature of this enzyme, a gatekeeper helix, is responsible for its specificity to fatty aldehydes.

One current focus is the characterisation of plasmanylethanolamine desaturase, which introduces the crucial double bond into plasmalogens, major glycerophospholipids in our brains and immune cell membranes. We have developed novel assays to characterise this reaction and been able to find the gene (TMEM189, PEDS1) that encodes this enzymatic activity.

^{Fig. 2: Ether Lipid Metabolism (simplified)}

Bioethics
Gabriele Werner-Felmayer

Current work is focusing on ethical, cultural and social dimensions in biomedicine, inspired by interdisciplinary cooperation. The main topics of research include new technologies in the context of assisted reproductive technologies and prevailing deterministic views in genetics/genomics and medicine. At present, the research is focused on consent models in organ transplantation and on developing modalities to increase awareness of ethical issues in data-driven medicine. Other activities include membership of Austria’s bioethics commission since 2017, the development of a compulsory ethics curriculum for medical students (with ao.Univ.Prof. Dr. Barbara Friesenecker, MUI, and Univ.Prof. Dr. Georg Gasser, University of Augsburg, Germany) and contribution to the Eurolife dataethics project (https://www.dataethics-eurolife.eu/).

Selected Publications

• Crystal structure of the human lysosomal mTORC1 scaffold complex and its impact on signalling. De Araujo, M.E.G., Naschberger, A., Fuernrohr, B.G., Stasyk, T., Dunzendorfer-Matt, T., Lechner, S., Welti, S., Kremser, L., Shivalingaiah, G., Offterdinger, M., Lindner, H., Huber, L.A., Scheffzek, K. SCIENCE 358, 2017, 377-381.
• On the possible relevance of bottom-up pathways in the pathogenesis of Alzheimer’s disease. Leblhuber F, Steiner K, Geisler S, Fuchs D, Gostner JM. TOP. MEDICIN. CHEM. 2020;20:1415-1421.
• Serum neopterin levels in relation to mild and severe COVID-19. Robertson J, Gostner JM, Nilsson S, Andersson LM, Fuchs D, Gisslen M. BMC INFECT. DIS. 2020; 20(1) 942, https://doi.org/10.1186/s12879-020-05671-7.
• The TMEM189 gene encodes plasmanylethanolamine desaturase which introduces the characteristic vinyl ether double bond into plasmalogens. Werner Ernst R, Keller Markus A, Sailer Sabrina, Lackner Katharina, Koch Jakob, Hermann Martin, Coassin Stefan, Golderer Georg, Werner-Felmayer Gabriele, Zoeller Raphael A, Hulo Nicolas, Berger Johannes, Watschinger Katrin. Proceedings of the National Academy of Sciences of the UNITED STATES OF AMERICA (2020); 117: S. 7792-7798
• Integrative Biology and Big-Data-Centrism: Mapping out a Bioscience Ethics Perspective with a S.W.O.T. Matrix: Überall, Martina, Werner-Felmayer, Gabriele, OMICS: 2019; 8: S. 371-379

Selection of Funding

• Structure of the neurofibromatosis type 1 protein, Austrian Science Fund (FWF), Klaus Scheffzek
• Alkylglycerol monooxygenase in Dictyostelium discoideum, Austrian Science Fund (FWF), Ernst R. Werner
• Closing the crucial genetic gap in plasmalogen biosynthesis. Austrian Science Fund (FWF), Ernst R. Werner
• AGMO: Impact on adipocyte differentiation. Austrian Science Fund (FWF), Katrin Watschinger

Collaborations

• Luciel Capuron, University of Bordeaux, France
• Keith Channon, Jonathan Hodgkin, University of Oxford, United Kingdom
• Pidder Jansen-Dürr, Leopold Franzens University, Innsbruck, Austria
• Frank McCormick, University of California San Francisco (UCSF), San Francisco, USA
• Andreas von Deimling, University Heidelberg, Heidelberg, Germany
• Magnus Gisslen, Lars Hagberg, Östra University Hospital, Gothenburg, Sweden
• Harald Mangge, Eva Reininghaus, Medizinische Universität Graz, Austria
• Teo T Postolache, University of Baltimore, MD, USA
• Richard W Price, Institut of Neurology, San Francisco General Hospital, UCSF, USA
• Markus Ralser, University of Cambridge, United Kingdom
• Thomas Rausch, University Heidelberg, Heidelberg Germany
• Barbara Prainsack, University of Vienna, Austria and Kings College London, UK
• Silke Schicktanz University Medicine Goettingen; Germany
• International Network of the UNESCO Chair in Bioethics, Haifa, Israel
• Research Center Medical Humanities, Leopold Franzens University, Innsbruck, Austria

Univ.-Prof. Dr.rer.nat Klaus Scheffzek
Director
Contact:
Innrain 80-82
6020 Innsbruck
Austria
Email: Klaus.Scheffzek@i-med.ac.at
Phone: +43 512 9003 70330
Fax: +43 512 9003 73110
https://www.i-med.ac.at/imcbc/molecularcellbiologyfolder/molcellbiol.html