Protein Biology > Protein Biology Group Leaders > Jakob R. Winther

Jakob R. Winther

Professor, Head of Section for Biomolecular Sciences

Research Activities

Thiol-disulfide chemistry of proteins

This work is mainly focused on protein thiol-disulfide biochemistry and on understanding the disulfide redox metabolism the eukaryotic cell, in particular in relation to the small thiol compound glutathione. We are designing and developing new tools based on a fundamental understanding of the chemistry involved. One of the more successful endeavors has been the design of a genetically encoded redox sensor based on the yellow fluorescent variant of Green Fluorescent Protein (GFP) which we have termed rxYFP.

We are presently paricularly interested in the cytosolic thiol-disulfide exchange enzyme glutaredoxin. This enzymes catalyzes the exchange of mixed disulfides between protein and glutathione in the reaction:

  -- where G signifies the glutathione moiety (γ-Glu-Cys-Gly).

This enzyme is centrally placed in the redox metabolism as glutathione is a highly abundant redox component in essentially all living organisms. In the cytosol the redox conditions are highly reducing and we have determined that the ratio between oxidized and reduced glutathione is in the order of 1/3000 using the rxYFP sensor.

Protein Design

In nature, proteins are able take on a huge range of functions both as structural entities and as enzymes, the latter being the most versatile and specific chemical catalysts known. Since the 1960s it has been understood that the protein structure is solely defined by its amino acid sequence. Following this realization, a huge effort has been made to predict protein structure from sequence, however, only recently are the daunting theoretical and computational challenges relating to this problem beginning to yield.

The emerging ability to predict structure from sequence opens the intriguing possibility of approaching the inverse problem of finding an amino acid sequence compatible with a predefined structure. Considering the diverse functional properties of proteins, the theoretical and practical implications of being able to build protein structure at will are tremendous.

Contemporary tools of chemistry and molecular biology allow protein sequences to be routinely generated from synthetic DNA and recent advances in the computational methods have made it possible in a few cases to design completely new proteins with specific and novel structures.

Using a simple model system we are investigating the design of new domains in a folded context. We have used a combination of methods to develop new proteins with more than 100 residues based purely on in silico design. Several of these constructs are currently being produced in E. coli and are subjected to biochemical and biophysical analysis. The project is part of a larger collaboration comprising the following researchers:
Jakob R. Winther, Department of Biology, University of Copenhagen, PI

Jesper Ferkinghoff-Borg, Institut for Elektroteknologi, Technical University of Denmark

Kaj Frank Jensen, Department of Biology, University of Copenhagen

Thomas Hamelryck, Department of Biology, University of Copenhagen

Jan H. Jensen, Department of Chemisty, University of Copenhagen

Leila Lo Leggio, Department of Chemisty, University of Copenhagen

Martin Willemoes, Department of Biology

This work is supported by Danish Agency for Science, Technology and Innovation.