Characterization of the CheAS/CheZ complex: a specific interaction resulting in enhanced dephosphorylating activity on CheY-phosphate
Article first published online: 31 OCT 2003
Blackwell Science Ltd, Oxford
Volume 19, Issue 4, pages 695–703, February 1996
How to Cite
Wang, H. and Matsumura, P. (1996), Characterization of the CheAS/CheZ complex: a specific interaction resulting in enhanced dephosphorylating activity on CheY-phosphate. Molecular Microbiology, 19: 695–703. doi: 10.1046/j.1365-2958.1996.393934.x
- Issue published online: 31 OCT 2003
- Article first published online: 31 OCT 2003
- Cited By
The cheA gene encodes two overlapping polypeptides with a common carboxyl terminus: CheAL and CheAS. CheAL plays a central role in the Escherichiacoli chemotaxis signalling pathway by autophosphorylation and transferring the phosphate to both CheY and CheB. On the other hand, the physiological functions of CheAS remain unknown.
We have observed that overproduction of CheAS in wild-type cells increased counterclockwise-biased flagellar rotation, and this effect is dependent on the presence of CheZ. CheZ specifically facilitates CheY-phosphate (CheY-P) dephosphorylation and generates a smooth swimming signal. A physical interaction was detected between CheZ and CheAS in wild-type cell lysates by immunoprecipitation. The CheAS/CheZ interaction does not require other chemotaxis components, as we could form the complex using purified CheAS and CheZ proteins. The ability of CheAS to bind to CheZ depends on its being in the reduced state. We found that under non-reducing conditions, CheAS appears to form intermolecular disulphide bonds and loses the ability to bind to CheZ. Finally, the CheAS/CheZ complex formed in vitro shows a greater dephosphorylating activity on CheY-P than does free CheZ.