Scientists at CCLRC Daresbury Laboratory and Farfield have been able to demonstrate the use of dual polarisation interferometry (DPI) to determine the earliest stages of crystallisation of a protein
X-ray crystallography provides probably the most important enabling technique for structural biology, but the crystallisation of proteins under study remains as the major bottleneck in the technique.
While understanding of crystal growth is well developed, there is a significant lack of techniques to investigate and understand the crystal nucleation events, without which crystal growth cannot proceed.
Scientists at CCLRC Daresbury Laboratory and Farfield Sensors, UK, have been able to demonstrate the use of dual polarisation interferometry (DPI) to determine the earliest stages of the crystallisation of a protein (nucleation).
The research has also revealed that it is possible to study the crystallisation of proteins that crystallise from precipitates.
Conditions under which nucleation proceeded, crystal nucleation did not proceed and in which the nucleation process took an extended period of time were clearly and uniquely identified.
Therefore DPI offers the potential to guide crystal growers in the search for crystallisation conditions, giving an indication of how to optimise these conditions and thus help remove a significant bottleneck in structural biology.
From preliminary data using the model protein lysozyme, the observation of the onset of crystallisation by DPI is consistent with molecular clusters of between 30 and 100 molecules, which can be considered to be the nucleation stage.
