Proteins turn up in many guises
Posted by Athene Donald on August 23, 2010
I have just come back from a brief trip to the Netherlands to discuss a project on protein aggregation at high concentrations with collaborators from NIZO (a Dutch food research organisation) and Eindhoven University. This project – funded by a Dutch Government source – ties in with my current work on protein aggregation of more medically relevant proteins, but is firmly directed at high protein content foods, where the aggregation can lead to a dry and unpalatable texture. My collaborators are two theoretical soft matter physicists and a polymer chemist who has spent the last 20 years working on food systems. And my own original entry into protein aggregation came via that route of foods, although most of my work is now a long way away from foodstuffs.
I think this exemplifies both the fun and the challenge of working in physics at the interface with biology. Within the UK there are rather few physicists working on food; and I think many mainstream physicists would still regard it as a rather odd activity. Physicists by and large may now accept biological physics – e.g. amyloid fibril formation – as a more reasonable research topic. And yet, the two areas in this case are essentially one and the same thing. The physics of the project I describe above could equally well apply to a study of interactions between proteins in the crowded environment of a cell; the cell contents are not just dilute dispersions of proteins as one might naively assume. but the proteins jostle one other because of their high concentration. Yet within the cell the proteins do their business effectively and, under normal circumstances, do not aggregate, unlike the unpalatable foods mentioned above. What seems to matter, in the foods, is how the high densities change the balance of intra- and inter-molecular bonding and the interaction with the water molecules. Other small solute molecules (e.g. salts) may also have a role to play in shifting the balance. There is much to understand at a basic level, which may in time lead to practical indicators for the food industry.
Incidentally, when I fly into the Netherlands, particularly at Rotterdam, less so at Schipol, I am always struck by the number both of wind turbines and also greenhouses. The country’s green credentials seem a bit confused and, as David Mackay makes plain in his fascinating book, most of the country would need to be covered by wind farms in order to raise a significant proportion of their energy consumption (though offshore installations are being built, and are significantly more productive).