Biochemistry

The biochemistry group led by Prof. Silvan Scheller brings chemical processes that evolved in nature to the laboratory for industrial applications.

Research themes

We focus on biocatalytic transformations that occur in nature but that are currently not possible in classical chemistry. In order to utilize such new metabolisms and enzymes, we first need to understand them in detail. For this reason, we carry out fundamental research in microbial physiology and mechanistic enzymology.

Microbes and Enzymes

We currently study the biochemistry and genetics of anaerobic archaea. Archaea from the deep-sea are able to convert methane or butane to CO₂ and single electrons. This metabolism may be applied for new methods to interconvert alkanes to electricity at ambient temperatures. The physiology of those environmental microbes is poorly understood and no pure cultures of them are available, preventing an industrial application. Our goal is to understand their biochemistry and the way how they are able to generate ATP from this process, in order to utilize this metabolism.

The first metabolic step is catalyzed by the enzyme methyl-coenzyme M reductase (Mcr) that converts alkanes to alkyl-thioethers via an unknown mechanism. Chemists are not able to perform such a reaction in the laboratory, which may change once we understand how nature is doing it.

Methodologies and Tools:

We perform genetic engineering with methanogens of the orders Methanosarcinales and Methanococcales. Due to their oxygen sensitivity, all manipulations are carried out in anaerobic chambers or incubators. Methanosarcina species are utilized as model organisms for the environmental process of alkane oxidation with release of single electrons. Methanococcus maripaludis is utilized as a genetic work horse for the expression of archaeal proteins and for designing new metabolic pathways.

We conduct mechanistic studies with enzymes purified from Methanothermobacter marburgensis, a methanogen that grows at 65 °C to high cell densities, allowing to access large amounts of native enzymes and cofactors. This organism is currently the only source to obtain the enzyme Mcr in the active form, which is prerequisite to study its catalytic mechanism. Biochemistry is studied by a range of different methods, such as: anaerobic expression of enzymes, experiments with isolated cofactors, kinetic studies, measurement of equilibria, electrochemistry, synthesis of substrate analogues, isotope effects, NMR and EPR studies, DFT calculations.

Publications

See List of Publications

http://scholar.google.com/citations?user=5nWRRZsAAAAJ&hl=en

PhD students and Postdocs:

If you are interested in joining the group with your own funding, please contact Silvan Scheller.

Group members:

Group Leader:

Silvan Scheller

Assistant Professor, 2017 onwards, Biochemistry (Aalto, FI)

Research Associate, 2016-2017, Biocatalysis (Zürich University of Applied Sciences, CH)

Postdoc, 2012-2016, Geobiology (California Institute of Technology, USA)

PhD, 2011, Organic Chemistry (ETH Zürich, CH)

Postdocs:

Norman Adlung

Norman got his PhD degree in the field of plant-pathogen interaction from the Martin Luther university Halle-Wittenberg, Germany in 2016.

Jichen Bao

Jichen got his PhD degree in the field of systems biology from Chalmers University of Technology, Sweden in 2018.

PhD Student:

Mradul Mishra

Master of Science in Microbiology, 2015-2017, (Friedrich Schiller University Jena, Germany)

Email: mradul.mishra [at] aalto [dot] fi

Undergraduates:

Irfan Mughal

Panu Inkinen