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One-Atom Linchpin

February 11, 2010

A single calcium atom can make or break a bacterium’s movement – and infectiousness.


A one-atom linchpin. I’m Bob Hirshon and this is Science Update.

In order to move across a solid surface – and infect a host – some bacteria form tiny legs called pili. The pili stick to the surface like grappling hooks, then retract to pull the bacteria along. Now, University of North Carolina biochemist Matthew Redinbo and his colleagues have found that all this hinges on a single calcium atom. The atom binds to a protein in tiny molecular motors that control the legs.

MATTHEW REDINBO (University of North Carolina):
And if you take that atom away – if you change the protein so that it can’t bind to calcium – the bacteria can’t make any legs.

Making the calcium bind permanently, on the other hand, prevented the bacteria from retracting their legs. Either way, the bacteria couldn’t move. Redinbo says exploiting this would be medically valuable, but hard to do, since calcium is vital to so many other cellular functions. I’m Bob Hirshon for AAAS, the Science Society.