9.B.344.  The Uncharacterized Archaeal 4 TMS Protein (UA4P) Family 

The proteins of the UA4P family are usually about 200 aas in length and have 4 TMSs often in a 1 +2 + 1 TMS arrangement.  They are found exclusively in archaea, mostly in Lokiarchaeota and Methanomassiliicoccus species.  In the latter organisms, there are both 4 and 8 TMS proteins.  In the latter, the two halves are both homologous to the 4 TMS proteins.  This provides evidence that these proteins may be transporters that function as homodimers of two 4 TMS proteins or as monomers of the 8 TMS proteins.



TC#NameOrganismal TypeExample

UP of 218 aas and 4 TMSs with a XrtN domain

UP of Candidatus Lokiarchaeota archaeon CR_4


Uncharacterized protein of 181 aas and 4 TMSs

UP of Candidatus Lokiarchaeota archaeon (sediment metagenome)


TC#NameOrganismal TypeExample

Uncharacterized protein of 167 aas and 4 TMSs

UP of Methanomassiliicoccales archaeon PtaU1.Bin030 (bioreactor metagenome)


Uncharacterized protein of 185 aas and 4 TMSs.

UP of Methanomassiliicoccales archaeon Mx-06 (human gut metagenome)


Uncharacterized protein of 171 aas and 4 TMSs.

UP of Methanomassiliicoccus luminyensis


Uncharacterized protein of 378 aas and 8 TMSs in a 4 + 4 TS arrangement.

UP of Methanomassiliicoccus sp. (marine sediment metagenome)


Uncharacterized protein of 166 aas and 4 TMSs.

UP of Candidatus Methanomassiliicoccus intestinalis (human gut metagenome)


Uncharacterized protein of 243 aas and 4 N-terminal TMSs with a C-terminal hydrophilic extension of about 100 aas.

UP of Euryarchaeota archaeon (subsurface metagenome)


Uncharacterized protein of 157 aas and 4 TMSs

UP of Thermoplasmata archaeon


Uncharacterized protein of152 aas and 4 TMSs

UP of an unidentified uncultured organism


Uncharacterized protein of 200 aas and 4 TMSs in a 1 + 2 + 1 TMS arrangement.

UP of Methanomassiliicoccales archaeon Mx-02 (human gut metagenome)


Uncharacterized protein of 313 aas with 5 TMSs in a 3 + 1 TMS arrangement with a 100 aa hydrophilic extention.

UP of Candidatus Lokiarchaeota archaeon (sediment metagenome)