Derivatisation of perdeuterated small molecules isolated from deuterated cell cultures (ILL, ESS)

Deuteration Network Members Involved: ILL, ESS

Project Description: The aim of the project is to develop methods for the extraction, separation and purification of deuterated lipids from cell cultures.

Interest in understanding lipid structure and function is rapidly increasing in the fields of biology and soft matter using neutron scattering techniques. However, to fully exploit its potential, increased contrast between components, using deuteration, is often essential. Deuterated lipids are time-consuming to synthesise chemically and therefore we are investigating a biological method for producing these small molecules.

By adapting specific organisms to grow on perdeuterated medium (all protium replaced by deuterium) we can access all the lipid molecules produced by the cell in their deuterated form. A comparison of the lipid composition of native fungal membrane extracts from the yeast Pichia Pastoris under protonated and deuterated conditions found that while phospholipid classes were maintained, the composition of fatty acids was impacted with significantly higher C18:1 fatty acids produced under deuterated conditions.

The extent of deuteration and the amount of material recovered is limited by the nature of the organism employed. We are therefore interested in determining the optimum organisms for producing large quantities of deuterated lipids for use by the neutron user community. Moreover, we are interested in organisms which produce lipids which are similar to those found in mammalian cells and therefore it is important that they produce phosphatidylcholine.

We have started the deuterium adaptation process on a range of acetobacter strains. Initial work has shown that their composition includes phosphatidylcholine, phosphatidylethanolamine and cardiolipin as well as a wide range of fatty acids. Once we have optimised the protocol for producing the lipids we intend to develop methods for their separation. While it is easy to separate the lipids based on their head groups it is much more complex to separate them by the nature of their fatty acid chains. We will therefore seek to find methods for the separation of lipids into their molecular species so that users can easily form membranes with known configurations matching those found within their biological system.