9.B.204.  The Prokaryotic 2 TMS domain Protein (Pr2TM) Family 

This family is widespread in bacteria and archaea.  The 2 TMS domain is referred to as 2TM with Pfam # 13239.  It may be involved in cell lysis or peptidoglycan turnover, and thus, could be a holin (TC subclass # 1.E).  Some of these proteins have a C-terminal MAS protein import receptor domain (Pfam # 02064).


TC#NameOrganismal TypeExample

Uncharacterized protein of 459 aas and 12 TMSs in a 4 + 4 + 4 arrangement.

UP of Lokiarchaeum sp. GC14_75


Two component sensor histidine kinase of 349 aas and 4 N-terminal TMSs, residues 1 - 140.

Kinase of Psychroflexus gondwanensis




Histidine sensor kinase (HSK) of 347 aas and 4 N-terminal TMSs, residues 1 - 140.

HSK of Psychroflexus gondwanensis


Histidine sensor kinase of 406 aas with 5 or 6 N-terminal TMSs between residues 1 and 200.

HSK of Bacteroides massiliensis


Uncharacterized protein of 90 aas and 2 TMSs.

UP of Gimesia maris


Uncharacterized protein of 101 aas and 2 TMSs.

UP of Phenylobacterium sp. Root700


Histidine sensor kinase of 514 aas and 8 TMSs with 4 TMSs at the N-terminus and 4 TMSs at the C-terminus.  The central hydrophilic domain is the sensor kinase, and the C-terminal consists of two 2TMS domains in close proximity to each other.  The N-terminal 4 TMSs do not appear to belong to the 2TMS family.

Sensor kinase of Galbibacter marinus


Uncharacterized protein of 168 aas and 4 TMSs.

UP of Lokiarchaeum sp. GC14_75


DUF1707 domain-containing proteinof 148 aas and 2 TMSs.

DUF1707 protein of Mycolicibacter heraklionensis


Uncharacterized protein of 163 aas and 4 TMSs in a 2 + 2 TMS arrangement.

UP of Methyloceanibacter marginalis


Histidine sensor kinase of 440 aas with 6 TMSs, 4 N-terminal (residues 1 - 140) and 2 C-terminal (residues 370 - 420). The last two TMSs are homologous to 2 of the 4 C-terminal TMSs in 9.B.304.1.4.

Sensor kinase of Maribacter sp.


Putative two-component system sensor protein, no kinase, of 450 aas with 6 TMSs in a 4 (N-terminal, residues 1 - 140) + 2 (C-terminal, resdiues 370 - 420).

Sensor of Polaribacter irgensii