Pure and unpure

A major topic he will be covering at AOHUPO is the challenge of mixed proteomes and his crusade for purity. His team has found that when cells are extracted from the homogenised lungs of infected animals, the strength of the Cryptococcus and its stickiness is actually quite useful.

"You can homogenise it and wash away all of the lung tissue and you are left with a really pure prep of Crypto, but even after repeated washing, if you then go in and strip that with lithium you then find a huge amount of lung and mouse proteins still stuck on the surface.

"People have to start to think purity doesn't exist anymore. You have this lovely tube full of lovely cells and you look at it down the microscope and you think you have washed it properly. Then you lay it on the gel and think there is nothing in it, but by putting lithium chloride on them and wash them in that, and then put them in the mass spectrometer, up comes huge numbers of mouse proteins.

"What we have learned from it is that lithium is a very powerful agent for disrupting interactions and we are now working with lithium as a stripping agent for membranes, for example. I have an honours student doing membrane protein work with lithium as a stripping agent instead of sodium. What I want to say to the audience up there is, don't get bogged down in dogma that something has been solved just because it has been published a hundred times. That doesn't mean it is right and you might find a better way."