User:Meili Yang/sandbox 1

One of the CBI Molecules being studied in the University of Massachusetts Amherst Chemistry-Biology Interface Program at UMass Amherst and on display at the Molecular Playground.

The bacterial chemotaxis receptors are transmembrane receptors with a simple signalling pathway which has elements relevant to the general understanding of signal recognition and transduction across membranes, how signals are relayed between molecules in a pathway, and how adaptation to a persistent signal is achieved.

Bacterial chemotaxis receptors are composed of a ligand-binding domain, a transmembrane domain consisting of two helices TM1 and TM2, and a cytoplasmic domain. All known bacterial chemotaxis receptors have a highly conserved cytoplasmic domain, which unites signals from different ligand domains into a single signalling pathway to flagella motors.

Cytoplasmic domainCytoplasmic domain

<applet load='1wat' size='[450,338]' frame='true' align='right' caption= 'cytoplasmic domain of a serine chemotaxis receptor(1qu7)' scene='User:Meili_Yang/sandbox_1/Cytoplasmic_domain/1'>

The structure of the cytoplasmic domain of a serine chemotaxis receptor(TSR) of Escherichia coli is a 200 A-long coiled-coil of two antiparallel helices connected by a 'U-turn'. Two of these domains form a long, supercoiled, four-helical bundle in the cytoplasmic portion of the receptor.