Molecular model of a lattice of signalling proteins involved in bacterial chemotaxis

Coliform bacteria detect chemical attractants by means of a membrane-associ ated cluster of receptors and signalling molecules. We have used recently d etermined molecular structures, in conjunction with plastic models generate d by three-dimensional printer technology, to predict how the proteins of t he complex are arranged in relation to the plasma membrane. The proposed st ructure is a regular two-dimensional lattice in which the cytoplasmic ends of chemotactic-receptor dimers are inserted into a hexagonal array of CheA and CheW molecules. This structure creates separate compartments for adapta tion and downstream signalling, and indicates a possible basis for the spre ad of activity within the cluster.