Building ‘nanomachines’ in biological outer space

New research reveals how bacteria construct tiny flagella ‘nanomachines’ outside the cell.

It’s exciting how economical bacteria are, able to harness the thermal free energy from unfolded subunits and convert it into a coherent directed transport
 - Dr Lewis Evans

Cambridge scientists have uncovered the mechanism by which bacteria build their surface propellers (flagella) – the long extensions that allow them to swim towards food and away from danger. The results, published this week in the journal Nature, demonstrate how the mechanism is powered by the subunits themselves as they link in a chain that is pulled to the flagellum tip.

Previously, scientists thought that the building blocks for flagella were either pushed or diffused from the flagellum base through a central channel in the structure to assemble at the flagellum tip, which is located far outside the cell. However, these theories are incompatible with recent research showing that flagella grow at a constant rate. The completely new and unexpected chain mechanism, in which subunits linked in a chain ‘pull themselves’ through the flagellum, transforms understanding of how flagellum assembly is energised.

The research was led by Dr Gillian Fraser and Professor Colin Hughes in the University’s Department of Pathology and was funded by the Wellcome Trust.


Read the full story


Image: Flagellated cell
Credit: Lewis Evans

Reproduced courtesy of the University of Cambridge
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