TCDB is operated by the Saier Lab Bioinformatics Group

9.B.320.  The 7 TMS Asgard Archaeal (7-AA) Family 

This family appears to consist of two distantly related subfamilies:  (1) a family of 7 (and sometimes 8) TMS archaeal proteins with an almost uniform topology of 7 TMSs.  Most of them are from the Asgard superphylum of archaea, but a few are from other archaea.  (2) the second family derives almost entirely from Actinobacteria, but a few are derived from bacteria belonging to other phyla.  While the first family consist almost entirely of small proteins with only the transmembrane domain, a few of these proteins and most of the proteins in the second family consist of the N-terminal 7 TMS domain followed by a substantial hydrophilic domain of variable size.  The latter proteins were identified as being part of this family based on BLAST seaches with iterations.  these searches also revealed the occasional occurance of G-protein receptors of Eukaryotes.