Research Topics
RUB » Department of Biophysics » X-ray structure analysis of proteins

Function of ABC transporters: MsbA


The structure of MsbA is known, however only low resolution data exists. We try to understand the mechanism, how ATP hydrolysis is coupled to the transport of Lipid A. Using classical biochemistry as well advanced biophysical methods such as FT-infrared spectroscopy, we aim to obtain dynamic information in atomic detail.

Syberg et al. (2012) Time-resolved Fourier transform infrared spectroscopy of the nucleotide-binding domain from the ATP-binding Cassette transporter MsbA: ATP hydrolysis is the rate-limiting step in the catalytic cycle. J Biol Chem 287: 23923-23931
doi: 10.1074/jbc.M112.359208.


Function of ABC transporters: Mycobacterium tuberculosis


Just like in other organisms, ABC transporters are vital for survival of Mycobacteria. Hence we study the function and structure of ABC transporters in order to understand their role in Mycobacteria physiology.
First results show, that we are able to purify an ABC transporter and are now optimising the purification protocol. This is crucial for structural studies of the protein and includes a vast number of tests. Hence, we are currently establishing functional assays for the transporter, which will give insight into their enzymatic function.



Biosynthesis of bilins is complicated and involves several redox reactions, which are catalysed by the proteins PebA and PebB. Subsequently, the bilins are handed over to lyases (see below). How PebA and PebB interact and catalyse bilin synthesis is unknown and will be investigated structurally as well as biochemically.


Pigmentchaperone: Structure and function of lyases


This enzyme shows a beta-barrel structure. Together with the group of Prof. Dr. Frankenberg-Dinkel, Kaiserslautern university, we aim to understand how bilins are bound and how the protein is able to perform the attachment of bilin to cysteine residues of phycobiliproteins.

Overkamp KE, Gasper R et al. Insights into the biosynthesis and assembly of cryptophycean phycobiliproteins. J Biol Chem (2014) 289, 26691-707. doi: 10.1074/jbc.M114.591131


Dinoflagellates: soluble light harvesting proteins

Schulte T, Johanning S, Hofmann E (2010) Structure and function of native and refolded peridinin-chlorophyll-proteins from dinoflagellates. Eur. J. Cell Biol 89: 990-997. doi:10.1016/j.ejcb.2010.08.004


Plant enzymatic reactions: Jasmonate biosynthesis

Currently we are testing this mechanistic model of AOC, and its interaction with the other two enzymes using biophysical and structural methods.

Hofmann E, Pollmann S (2008) Molecular mechanism of enzymatic allene oxide cyclization in plants. Plant Physiol. Biochem 46: 302-308. doi:10.1016/j.plaphy.2007.12.007


New antibiotics: Function of the Lipid II transporter FtsW


Penicillin-binding proteins (PBPs) sit inside the bacterial cell membrane and concatenate Lipid II molecules into the bacterial cell wall.
FtsW is one of two candidate proteins that transports Lipid II across the cell membrane in order to hand over lipid II to the PBPs. Hence it's the best target protein to test for new antibiotics.
We are now able to purify and indeed crystallize the protein. We aim to firstly solve the structure of FtsW and secondly develop a functional assay that allows us to test and identify inhibitory substances. Those would immediately constitute a new antibiotics class.