The CheW-like domain is an around 150-residue domain that is found in proteins involved in the two-component signaling systems regulating bacterial chemotaxis. Two components systems are composed of a receptor kinase, which monitors the environmental conditions and its substrate, the response regulator, which acts as a binary switch depending on the phosphorylation state. In Escherichia coli … expand

The CheW-like domain is an around 150-residue domain that is found in proteins involved in the two-component signaling systems regulating bacterial chemotaxis. Two components systems are composed of a receptor kinase, which monitors the environmental conditions and its substrate, the response regulator, which acts as a binary switch depending on the phosphorylation state. In Escherichia coli, the signal transduction pathway for chemotaxis consists of specialised membrane receptors, termed chemotaxis transducers; a CheA-CheY two-component system, which transmits the signal from transducers to flagellar motors; and a docking protein, CheW, which couples the CheA histidine kinase to transducers. Whereas CheW is only made of a CheW-like domain, CheA additionally contains an HPt domain and an histidine kinase domain. The CheW-like domain has been shown to mediate the interaction between CheA and the adaptor protein CheW. Some bacteria contain another bifunctional protein, CheV, consisting of an N- terminal CheW-like domain and a C-terminal response regulatory domain. Although its precise function in chemotaxis is unknown, CheV probably acts in adaptation to attractants [ PUBMED:9989504 PUBMED:11553614 PUBMED:12511501 PUBMED:11799399 ].

The CheW-like domain is composed of two β-sheet subdomains, each of which forms a loose five-stranded β-barrel around an internal hydrophobic core. The interactions between the subdomains are contributed by a third hydrophobic core sandwiched between the two β-sheet subdomains. The CheW-like structure is stabilised by extensive hydrophobic interactions [ PUBMED:9989504 PUBMED:11799399 ].