Biological macromolecules differ from the small molecules found in organic chemistry in their size and complexity. Most notably, they can be thought of as machines, which truly operate on the nanoscale and can only be understood when we take into account their mechanical, as well as their chemical, properties.

The ATP synthase molecule, shown as an example, is responsible for generating virtually all of the energy in a cell. It consists of a 'motor' and a 'dynamo' connected by a rotating 'driveshaft'.

Unlike man-made nanomachines, these devices are fabricated to atomic precision, are self-assembling and (at least within a cell) self-repairing, and have been fine-tuned to perform their functions through many millions, or even billions, of years of evolution. They can also be produced in vast numbers at a relatively low cost.

However, before we can apply such machines, we really need to understand how they work. Conventional biochemical and structural biology approaches can yield a great deal of useful information, but often to understand mechanism we need to use single molecule approaches. In my talk I will give examples of these amazing biological machines, and show how single molecule approaches have been used to understand their intricacies.

Alex Knight is a Senior Research Scientist in Biotechnology; currently the Technical Area leader for Molecular Biophysics.