General introduction of the "Protein Folding and Stability" group

Carlo P.M. van MierloGroup Leader: Carlo P.M. van Mierlo

Since the first three-dimensional structures of proteins were elucidated the problem of how proteins fold to such complicated structures has been debated.  The subject of this debate is called the protein folding problem which is one of he major challenges in contemporary molecular biology. The understanding of protein folding would imply that the link between protein sequence, structure stability and, ultimately, function is dissected. The topic has wide-ranging impact in fields like structural biology, materials science, and medicine. It was Anfinsen with his co-workers who demonstrated that in principle proteins can fold unassistedly and reversibly to their native three-dimensional state in which they are biologically active.  Consequently, all the information required to define the tertiary fold is encoded in the amino acid sequence.  Folding does not occur via a random sampling of conformational space as this would take longer than the life time of the universe.  Most proteins however, fold within milliseconds to minutes.  To explain the latter, among others, the concept of protein folding pathways arose.

The understanding of how proteins fold should answer a few related questions:

* what is the physical basis of the stability of the folded protein conformation
* what processes determine that a protein adopts its native conformation
* what are the rules that link the amino acid sequence with the three-dimensional structure of a protein
* and finally, can the three-dimensional structure of a protein be predicted from its amino acid sequence?

Besides that the answers to these questions are of academic interest, knowledge about protein folding is nowadays being exploited in many practical applications in biotechnology and is thus also of industrial importance. 

General rules governing protein folding are now beginning to emerge.  An important breakthrough was the realisation that there is not a single, specific protein folding pathway but that instead, a multidimensional energy landscape or folding funnel better describes the folding process. In principle, there are many routes to the native state and which pathways will be populated depends on the details of the system under investigation (e.g. the amino acid sequence, the topology and the experimental conditions).

The research programme of the group of Carlo van Mierlo is centred around protein folding and stability (see the links to current and previous research subjects of the group at the bottom of this web page).  It comprises the experimental investigation of: protein folding pathways, global and local stabilities of proteins, their internal dynamical behaviour, and the elucidation of the structures of proteins in solution. 

Currently, the group uses single-molecule fluorescent energy transfer confocal microscopy, ultrafast polarised fluorescence spectroscopy, and NMR spectroscopy in oriented systems to elucidate the folding in vitro of the protein flavodoxin. These techniques reveal details of flavodoxin's folding energy landscape in vitro and insight into the events that are expected to occur in the earliest stages of protein folding is obtained.

Contact for further information:

Carlo P.M. van Mierlo
Laboratory of Biochemistry
Wageningen University
Dreijenlaan 3
6703 HA Wageningen
The Netherlands

Current research subjects (and researchers involved)

Characterisation of the structure and dynamics of the unfolded state of apoflavodoxin by NMR and optical spectroscopy (Sanne M. Nabuurs and Carlo P.M. van Mierlo)

Flavodoxin (un)folding in vitro studied by single-molecule optical detection techniques (Ruchira Engel, Ton Visser, Carlo P.M. van Mierlo)

Flavodoxin (un)folding in vitro studied by ultrafast optical ensemble measurements (Niels de Keijzer, Herbert van Amerongen, Carlo P.M. van Mierlo)

Biochemical and Biophysical characterisation of flavodoxin folding (Adrie Westphal and Carlo P.M. van Mierlo)

Structure determination of membrane peptides of the vacuolar ATP-ase complex by NMR spectroscopy (Afonso Duarte, Marcus Hemminga, Carlo P.M. van Mierlo)

Previous research subjects (and researchers involved)

Structure, stability and equilibrium (un)folding of flavodoxin (Elles Steensma and Carlo P.M. van Mierlo)

Surfing the free energy landscape of flavodoxin folding in vitro (Yves J.M. Bollen and Carlo P.M. van Mierlo)

Detailed characterisation of adsorption-induced protein unfolding (Maarten F. M. Engel, Ton Visser, Carlo P.M. van Mierlo)

(Un)folding, aggregation and stability of individual protein molecules in complex protein mixtures (Hans Ippel and Carlo P.M. van Mierlo)

Unravelling the molecular basis of the extreme stability of an endoglucanase (Sotiris Koutsopoulos, Hans Ippel, Willem Norde, John van der Oost and Carlo P.M. van Mierlo)

Publications of the group

Techniques and methods used by the group

General introduction of the research group