9.B.334.  The Archaeal N-terminal Transmembrane  Domain Linked to a Sensor Kinase or MCP Domain (N-TM/SK/MCP) Family 

These archaeal proteins have an N-terminal transmembrane domain followed by a SK or MCP domain.  There seems to exhibit tremendous variation in the combinations of these domains. They are grouped together here as their primary function is probably determined by the hydrophilic domain.  The transmembrane domains may serve as membrane anchors.



Bibikov, S.I., R. Biran, K.E. Rudd, and J.S. Parkinson. (1997). A signal transducer for aerotaxis in Escherichia coli. J. Bacteriol. 179: 4075-4079.

Maschmann, Z.A., T.K. Chua, S. Chandrasekaran, H. Ibáñez, and B.R. Crane. (2022). Redox properties and PAS domain structure of the Escherichia coli energy sensor Aer indicate a multistate sensing mechanism. J. Biol. Chem. 298: 102598.


TC#NameOrganismal TypeExample

UP of 387 aas with 7 N-terminal TMSs and a C-terminal methyl-accepting chemotaxis protein 3 domain.

UP of Lokiarchaeum sp. GC14_75


Uncharacterized sensor histidine kinase of 434 aas and 6 TMSs with a COG0642 domain.

UP of Lokiarchaeum sp. GC14-75


The aerotaxis protein, Aer or YqjJ of 506 aas and 1 or 2 TMSs. The aerotactic response causes the accumulation of cells around air bubbles in liquid media under a cover slip. The nature of the sensory stimulus detected by this protein is the proton motive force (pmf) and the cellular redox state. It uses an FAD prosthetic group as a redox sensor to monitor oxygen levels (Bibikov et al. 1997). The redox properties and PAS domain structure of  Aer indicate a multistate sensing mechanism (Maschmann et al. 2022).

Aer of E. coli


TC#NameOrganismal TypeExample