9.B.109 The Putative Archaeal 2 TMS Holin (A2-Hol) Family

The archaeon, Candidatus Nitrosoarchaeum limnia, encodes adjacent genes designated Toxin Secretion/Lysis Holin.  The 'toxin' gene encodes a soluble protein of 325 aas stated as belonging to the 'Glycosyltransferase GBT-type Superfamily'.  This protein brings up other glycosyltransferases in NCBI BLAST searches. The adjacent gene encodes as small protein of 132 aas and 2 TMSs that could be a holin, based on its size and topology, but it could also be a 2 TMS counterpart to the other 2 TMS protein of a two-comoponent transport system. This is suggested because several members of the family have 4 TMSs instead of 2 TMSs.  The first protein has the UniProt accession number of S2E3C4 and has been assigned TC# 9.B.109.1.1.  Paralogues are found in this same organism and other closely related species. This TC family (9.B.109) appears to be related to TC family 9.B.116 which shows significant sequence similarity with members of 9.B.109 and has the same topology with members having either 2 or 4 TMSs.


Examples:

TC#NameOrganismal TypeExample
9.B.109.1.1

Putative holin of 132 aas and 2 TMSs.

Thaumarchaeota

Putative holin of Candidatus Nitrosoarchaeum limnia

 
9.B.109.1.2

Putative holin of 157 aas and 2 TMSs

Thaumarchaeota

Putative holin of Candidatus Nitrosoarchaeum limnia

 
9.B.109.1.3

Putative holin of 165 aas and 2 TMSs

Thaumarchaeota

Putative holin of Candidatus Nitrosoarchaeum koreensis

 
9.B.109.1.4

Putative holin of 121 aas and 2 TMSs.

UP of Nitrosopumilus sp. Nsub

 
9.B.109.1.5

Putative holin of 179 aas and 2 TMSs

UP of uncultured marine thaumarchaeote SAT1000_07_E05

 
9.B.109.1.6

Uncharacterized protein of 202 aas and 2 TMSs

UP of Ignicoccus islandicus

 
9.B.109.1.7

Uncharacterized protein of 144 aas and 2 TMSs.

UP of Candidatus Heimdallarchaeota archaeon B3_Heim (marine sediment metagenome)

 
9.B.109.1.8

Uncharacterized protein of 115 aas and 2 adjacent N-terminal TMSs.

UP of Archaeoglobales archaeon (marine sediment metagenome)

 
Examples:

TC#NameOrganismal TypeExample
9.B.109.2.1

Uncharacterized protein of 170 aas and 2 N-terminal TMSs.

UP of Ignicoccus islandicus