FLI Jena - Biomolecular NMR Spectroscopy

Current projects

The systems we are working on include proteins involved in the repair of oxidative damage of proteins and DNA, oncoproteins and RNA signal structures of viruses, which may cause cancer, and aggregates of proteins or of a triplet repeat expansion involved in the pathogenesis of degenerative diseases. In this context, we are also engaged in developing techniques for solid state NMR, which is a powerful tool for the structural characterisation of biomolecules not amenable to investigation by solution state NMR or X-ray crystallography.

Repair of oxidative damage

Oxygen, although essential for life, may be dangerous to cells because of the formation of reactive oxygen species (ROS). ROS cause damage to nucleic acids, proteins and lipids. One major ageing theory holds, that accumulation of oxidative damage constitutes one of the major causes of aging and age-related diseases.
Oxidative damage of proteins by ROS frequently leads to non-reversible modification of the polypeptide chain, including chain breaks, which in turn compromises or abolishes protein function. The oxidation of methionine to methionine sulfoxide, however, can be "repaired" by methionine sulfoxide reductases (MSRs).
The action of ROS upon DNA may lead to deleterious base modifications or single strand breaks (SSB). Such damages are recognised and corrected by DNA repair proteins. Some steps along this pathway require "proofreading" activities to remove obstructive termini, which would hamper the final ligation step.
Our goal is to solve the molecular structures of such proteins and to characterise their molecular interactions with substrates, in order to provide a detailed insight into their respective mechanism of action.
Collaborations: Z.Q. Wang (FLI) and S. Heinemann (FSU Jena), W. Meyer-Klaucke (DESY, Hamburg)
Repair oxidative damage

The oncoproteins E6 and E7 of human papilloma viruses (HPV)

HPV cause several human diseases ranging from benign manifestations to debilitating malignancies. The HPV oncoproteins E6 and E7 are involved in the pathogenesis and maintenance of human cervical cancers, which typically develop decades after initial infection.
Both oncoproteins excert their malicious activity by interacting with cellular key regulator proteins, thereby confounding or abrogating the delicate orchestration of the cell cycle, apoptosis, cytoskeletal organisation and cell polarity.
We aim at understanding the molecular properties of the HPV oncoproteins and their interaction with cellular proteins at the structural level, which may eventually contribute to developing agents specifically intercepting such deleterious interactions.
Collaborations: A. Ploubidou, H. Morrison, F. Grosse (FLI), M. Dürst (FSU Jena), W. Meyer-Klaucke (DESY, Hamburg)
Oncoprotein

Structural analysis of amyloid aggregates

Tissue deposits of amyloid aggregates are the hallmark of a diverse group of serious human diseases, including Alzheimer's disease, Creutzfeldt-Jakob disease and type II diabetes. Increasing evidence suggest that such aggregates are in these cases the main contributors to pathogenicity. The lack of precise structural knowledge about these different forms of amyloid aggregates severely limits our understanding of the structural basis of amyloid diseases and hampers the rational search for potential therapeutic agents. Therefore, we analyze the molecular structure of pathogenic aggregates employing different spectroscopical techniques, including FTIR, circular dichroism and NMR spectroscopy.
Collaborations: M. Fändrich (FLI, now MPG research unit, Halle)

Prefibrillar Aggregate 1

Prefibrillar Aggregate 2

Viral RNA signal structures

Many viruses depend upon RNA signal structures to accomplish their propagation cycle inside the infected cell. In this context we are addresing two viral systems.
Chronic infection with Hepatitis B Virus (HBV) may lead to liver cirrhosis and/or hepatocellular carcinomas. Transcription of the HBV DNA genome gives rise to intron-less mRNAs. The nuclear export of these unspliced RNAs encoding the viral proteins is facilitated by the cis-active hepatitis B virus post-transcriptional regulatory element (HPRE), which is located in the 3´-region of all viral transcripts.
Enteroviruses cause a number of acute and chronic diseases. Their small positive strand RNA genome carries signal structures, including a 5´-cloverleaf-like element and the viral IRES, which recruit both virally and host cell encoded proteins. These specific RNA:protein complexes play an essential role in viral cap-independent translation and RNA replication, respectively.
We aim to understand the structural basis of specific viral RNA:protein recognition, which may pave the way for finding substances modulating such interactions.
Collaborations: R. Zell (FSU Jena), R. Hilgenfeld (Univ. Lübeck) and T. Heise (Med. Univ. SC, Charleston, USA)
Solide State NMR

Development of solid state NMR Methods

Expansions of short nucleotide sequence repeats are associated with a number of degenerative diseases. A triplet repeat expansion in the dmpk gene gives rise to extended noncoding CUG triplet repeats on the RNA level, which sequester alternative splicing factors, the MBNL proteins. This trans dominant effect ultimately causes the adult onset muscular dystrophy (DM1). MBNL:CUG repeat complexes, however, form insoluble aggregates.
Magic angle spinning solid state NMR (MAS ssNMR) is emerging as a tool for the structural characterisation of biomolecules. It holds promise for systems, which are, e.g. due to their aggregation behaviour, difficult to study by solution state NMR or by X-ray crystallography.
We aim to explore and exploit the potential of this technique for the structural study of RNA molecules, which are involved in pathogenesis, such as the CUG triplet repeat expansion or viral RNA signal structures and, if possible, their protein complexes.
Collaborations: M. Swanson (Univ. Florida, Gainesville, USA), C. Glaubitz (highest field solid state NMR facility, Univ. Frankfurt)
Solide State NMR
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Last update: May 08, 2008