Promotor: M. Ubbink, Co-promotor: G. Siegal

The thesis describes the use of electron paramagnetic resonance (EPR) spectroscopy, in continuous wave and pulse modes, to address the interaction of α-Synuclein (αS) with membranes and the aggregation of αS.

Membrane proteins and membrane interactions of proteins are studied by spin label EPR. Intact, native membranes, vesicles of all sizes and nano-disks can be investigated, because the size of the object does not matter in EPR. Whereas solution NMR is limited to micelles (a few nm in diameter), by EPR…

Promotor: J.G.E.M. Fraaije, Co-Promotor: A. Kros

Solar energy harnessed by plants and algae has great potential to be converted into biofuels for future generations.

Alexander Kros and co-workers describe how mesoporous silica nanoparticles (MSNs) are delivered into cells via membrane fusion thereby omitting endocytosis pathways. Fusion is induced by a pair of complementary coiled-coil lipopeptides inserted into the membrane of cells and in the bilayer of lipid-coated…

The lipid membrane is a basic structural component of all living cells. Embedded in this nanometer-thin barrier, membrane proteins shape the membrane and at the same time respond to the shape of the membrane.

The plant hormone auxin plays a central role in the growth and development of plants. Auxin acts in a concentration dependent manner and polar cell-to-cell transport of this hormone determines its distribution in the tissues of plants. This polar auxin transport is mediated by several families of auxin…

Multicellular giant algae Chara species have been widely used in physiological studies for decades.

The Protein Centre can supply you with purified proteins that are essential for many experiments, ranging from in vitro inhibitor screening and enzymatic analysis to manipulation of life cells.

Promotor: A. Kros

Α-synuclein, a protein associated with Parkinson’s disease, proves to bind with membranes in a surprisingly efficient way. It confirms scientists’ suspicion of the protein’s leading role in the transmission of neurotransmitters between nerve cells in the brain. Publication in PLoS ONE.

This thesis describes the use of bioorthogonal proteins in immunological settings. It provides an introduction towards the field of protein modification, which was used throughout the thesis for the expression of proteins containing unnatural amino acids.

Promotor: Prof.dr. E.J.J. Groenen

How can we develop a new microscope that can distinguish individual atoms in proteins?

We have recently discovered that there are biological proteins that phase separate out of solution much the way oil will de-mix from water (see movie). These form dense, liquid-like phases called protein condensates.

The European Research Council (ERC) has awarded chemist Dr Alexander Kros a Starting Independent Researcher Grant of 1.4 million euro. He will be using the grant to study how molecules penetrate the natural barrier of a cell membrane. If his research is successful, it will in time bring about a revolution…

Supervisor: Xue Yang

Promotor: Prof.dr. C.A.M.J.J. van den Hondel, Dr. ir. V. Meyer, Co-promotor: Dr. A.F.J. Ram

Promotor: A. Kros

Oxidation is a common degradation pathway that affects therapeutic proteins and peptides during production, purification, formulation, transportation, storage and handling of solid and liquid preparations. In the present work we review the scientific literature about structural and biological consequences…

The current resurgence of whooping cough is alarming, and improved pertussis vaccines are thought to offer a solution. Outer membrane vesicle vaccines (omvPV) are potential vaccine candidates, but omvPV-induced humoral responses have not yet been characterized in detail.

Artificial photosynthesis aims to produce fuels from solar energy using chemical processes. In semi-artificial photosynthesis, a hybrid approach is taken using both chemical and biotechnology approaches. We aim to develop hybrid systems between light-harvesting nanoparticles and redox-enzymes (oxidoreductases)…

Some species of proteins which can form liquid-like condensates, also exhibit growth into fibers (or fibrils). One particularly interesting set of such proteins are those that are associated with neurodegeneration in which the fiber growth may be related to the pathological fibrils observed in disea…

Promotor: M. Ubbink, Co-promotor: G. Siegal

Plants, algae and cyanobacteria have the amazing capacity to perform delicate photophysical and photochemical processes of light capture, excitation transfer, charge separation and catalysis in fluctuating living environments. As a consequence, photosynthetic proteins and membranes form dynamic architectures.…

Plants, are sessile organisms, have developed strategies to adapt to changes in their environment, in part by altering their growth and development.

A structural investigation of coiled coil peptides used as membrane fusogens, mimicing naturally occuring coiled-coil fusion proteins. Synthetic modifications have been made to alter lipid attachment, secondary structure and to insert photoactive azobenzene moieties for active control over coiled coil…

Promotor: M. Ubbink, Co-promotor: G. Siegal

G protein-coupled receptors (GPCRs), one of the largest families of membrane proteins, are responsive to a diverse set of physiological endogenous ligands including hormones and neurotransmitters.

Supervisor: P.J.J. Hooykaas Co-Supervisor: R. Offringa

Promotor: W. Jiskoot, Co-promotor: A. Hawe

The skin barrier function is provided by the stratum corneum (SC). The lipids in the SC are composed of three lipid classes: ceramides (CERs), cholesterol (CHOL) and free fatty acids (FFAs) which form two crystalline lamellar structures. In the present study, we investigate the effect of CER chain length…

Promotor: H.S. Overkleeft, Co-promotor: M. van der Stelt

Research projects for students of the University of Leiden and other Dutch Universities are often available at the MacBio group. The research lines are also described in the Research section. For details of specific projects contact the supervisor (Ubbink, Dame, Boyle, Jeuken or Wentink).

Extending our current arsenal of antibiotics is key to staying ahead in the arms race between humans and resistant bacteria.

In our research protein translocation from Agrobacterium into yeast and plant cells is studied to obtain fundamental insights in the translocation process

In the last decades, activity-based protein profiling (ABPP) has emerged as a powerful chemical tool that may aid the ever-challenging drug discovery process.

Promotor: J.G.E.M.Fraaije, Co-promotor: A. Kros

Glycosidases are important enzymes in the turnover of polysaccharides and glycoconjugates, and are involved in a range of human pathologies including genetic disorders such as Gaucher and Pompe disease, but also in various cancers.

In this study, we evaluated the influence of supercritical carbon dioxide (scCO2) spray drying conditions, in the absence of organic solvent, on the ability to produce dry protein/trehalose formulations at 1:10 and 1:4 (w/w) ratios.

Hass

The RNA guided endonuclease based on the CRISPR/Cas system of Streptococcus pyogenus is a potent new tool for genome engineering in plants.

Membrane fusion is a vital process in living organisms and is mediated by zipper-like proteins.

Science, Leiden Institute of Chemistry (LIC)

Barrier function is the natural role of the skin. The lipid matrix present in the outermost layer of the skin, the stratum corneum is important for this function.

How can the transport of molecules in living cells help to target medicines at exactly the right place?