Simon Kolstoe Lab
Simon came to Portsmouth from UCL in April 2012 and is interested in the structure and function of immune related proteins. His group uses the mammalian HEK293 expression system to produce protein for structural and biophysical studies. The group has a wide network of collaborators and contributes structural data to a number of drug development projects. Specific expertise includes X-ray crystallography, isothermal titration calorimetry and in silico molecular docking. A second interest is in Research Ethics.
Our current laboratory research
Serum amyloid p component
Serum amyloid p component (SAP) is a protein found in the blood of all individuals. SAP also makes up 14% of amyloid deposits found in diseases such as the systemic amyloidosis, Creutzfeldt-Jakob disease, Alzheimer’s and type II diabetes. Small molecules that deplete SAP are currently undergoing clinical trials for the treatment of a variety of amyloid related disorders. Despite this good progress very little is understood about how SAP interacts with other molecules. One way to explore this is by creating mutant versions of the protein. Normally mutants can be made using bacterial expression systems but this has not worked for SAP because of a number of long sugar chains. We have recently shown that good levels of SAP can be produced in human embryonic kidney (HEK) cell cultures, and are now using mutagenesis to explore SAP’s various binding interactions. One interaction of note is between SAP and nucleic acids such as DNA and RNA. We are exploring the possibility that SAP may serve a role as an immune scavenger of nucleic acids and therefore contribute to diseases such as systemic lupus erythematosus.
Transthyretin (TTR) is a human serum protein that contributes to the diseases systemic amyloidosis and cardiac amyloidosis. Although normally a tetramer, mutations can result in the protein subunits misfolding, disassociating, aggregating and depositing in various organs. Observations from the three-dimensional structure of TTR led to the design of a new class of inhibitor molecules that are currently undergoing drug development. These molecules are able to stabilize the native TTR tetramer by binding through the middle of the protein, thus preventing subunit dissociation. Over 150 structures of TTR complexed to potential drug compounds have since been solved using X-ray crystallographic data obtained at the Diamond and ESRF synchrotron radiation facilities. Molecular level knowledge of how individual drugs bind to TTR have contributed to the design of new, higher potent, compounds.
Fc Gamma receptors
Fcγ receptors play an important role in the adaptive immune system by inducing phagocytosis of cells and debris opsonized by IgG. FcγR has also been reported to recognise the innate immune protein SAP. If confirmed this interaction suggests a greater level of immunological complexity than previously thought. FcγR are being expressed using the HEK expression system and their interaction with SAP explored using a variety of biophysical and structural methods.
C reactive protein
C-reactive protein (CRP) is a clinical marker of inflammation and shares over 50% sequence homology with SAP. Using knowledge gained from the SAP project small molecules that deplete serum CRP levels have been designed and their co-crystal structures solved using X-ray crystallography.