*9.A.22 The Putative Bacillus* Transporter of Unknown Function (BTUF) Family** A single 6 TMS protein, originally termed NhaE of Bacillus pseudofirmus OF4, had been reported in TCDB as an exchanger of H⁺ for either Na⁺ or K⁺ , but the results were not reproduced and a paper was not published. Members of this family are therefore of unknown function.
This family belongs to the MusI (MusI) Superfamily.
References:
Cheng, J., A.A. Guffanti, and T.A. Krulwich. (1997). A two-gene ABC-type transport system that extrudes Na⁺ in Bacillus subtilis is induced by ethanol or protonophore. Mol. Microbiol. 23: 1107-1120.
Examples:
TC#	Name	Organismal Type	Example
9.A.22.1.1	The NhaE Na⁺/K⁺:H⁺ antiporter. The gene encoding this protein is adjacent to genes encoding a GntR transcriptional regulator, two ABC ATPases designated NatA1 and NatA2 and an ABC membrane protein designated NatB, all possibly within a single operon.	Bacteria	NhaE (orf 14) of Bacillus pseudofirmus

9.A.22.1.2	Hypothetical protein. The encoding gene is adjacent to genes encoding a GntR transcriptional regulator (Q9KDP7), two ABC ATPases (Q9KDP6 and 7) and a putative ABC membrane protein (Q9KDP5), all possibly in a single operon.	Firmicutes	HP of Bacillus halodurans

9.A.22.1.3	Hypothetical protein. Encoded by a gene adjacent to genes encoding a GntR transcriptional regulator, a similar membrane protein with 6 TMSs in a 2 + 4 arrangement, followed by two genes encoding two ABC ATPases annotated as NatA1 and A2, followed by a membrane protein annotated as NatB2. These genes may all be in a single operon.	Firmicutes	HP of Bacillus cellulosilyticus

9.A.22.1.4	Uncharacterized protein of 241 aas and 6 TMSs.		UP of Alkalibacillus haloalkaliphilus

9.A.22.1.5	Uncharacterized protein of 251 aas and 6 TMSs in a 2 + 4 TMS arrangement.		*UP of Salilacibacter* sp. NKC3-5**

9.A.22.1.6	Uncharacterized protein of 243 aas and 6 TMSs in a 2 + 2 + 2 TMS arrangement.		*UP of Geomicrobium* sp. JCM 19039**

9.A.22.1.8	Putative 3-component ABC transporter with two membrane proteins, both of 6 TMSs in a 2 + 4 TMS arrangement and a single ATPase. This system is encoded by 3 genes that are adjacent to each other and a GntR transcription factor gene, and also to a putative Na⁺ ABC efflux system, NatAB (see 3.A.1.115.4; Cheng et al. 1997).		Putative 3 component ABC transport system with two membrane proteins (E6TQK3 and 4), and one ATPase (E6TQK6), possibly regulated at the GntR-type transcriptional factor (E6TQK5) of Evansella cellulosilytica (Bacillus cellulosilyticus)

Examples:
TC#	Name	Organismal Type	Example
9.A.22.2.1	Uncharacterized protein of 243 aas and 6 TMSs.	Firmicutes	UP of Bacillus clausii

9.A.22.2.2	Uncharacterized protein of 240 aas ans 6 TMSs		UP of Alkalihalobacillus lonarensis

Examples:
TC#	Name	Organismal Type	Example
9.A.22.3.1	Uncharacterized 6 TMS protein. Clearly a member of the 9.A.22 family, but also exhibits sequence similarity to the second half (TMSs 7 - 12) of the MFS permease, 2.A.1.62.3.	Firmicutes	UP of Paenibacillus terrae

9.A.22.3.2	Uncharacterized protein of 235 aas and 6 TMSs.		*UP of Thermoactinomyces* sp. DSM 45892**

9.A.22.3.3	Uncharacterized protein of 249 aas and 6 TMSs.		UP of Salinibacillus kushneri

9.A.22.3.4	Uncharacterized protein of 229 aas and 6 TMSs.		UP of Thermomicrobiales bacterium (activated sludge metagenome)

9.A.22.3.5	Uncharacterized protein of 241 aas and 6 TMSs		UP of Paenibacillus montaniterrae

9.A.22.3.6	Uncharacterized protein of 248 aas and 6 TMSs in a 2 + 3 + 1 TMS arrangement.		UP of Hazenella coriacea

Examples:
TC#	Name	Organismal Type	Example
9.A.22.4.1	Uncharacterized protein of 237 aas and 6 TMSs.		UP of Chryseobacterium gleum

9.A.22.4.2	Uncharacterized protein of 224 aas and 6 TMSs		UP of Sphingopyxis sp. MC1

9.A.22.4.3	Uncharacterized protein of 229 aas and 6 TMSs		UP of Ensifer adhaerens (Sinorhizobium morelense)

Examples:
TC#	Name	Organismal Type	Example
9.A.22.5.1	Uncharacterized protein of 300 aas and 6 TMSs in a 2 + 2 + 2 TMS arrangement.		*UP of Candidatus Peribacter riflensis* (groundwater metagenome)**

9.A.22.5.2	Uncharacterized protein of 358 aas and 6 TMSs in a 2 + 2 + 2 TMS arrangement.		*UP of Candidatus Gracilibacteria bacterium* CG2_30_37_12 (groundwater metagenome)**

9.A.22.5.3	Uncharacterized protein of 318 aas and 7 or 6 TMSs in a 2 + 2 + 2 or 3 TMS arrangement.		UP of Candidatus Magasanikbacteria bacterium (groundwater metagenome)

9.A.22.5.4	Uncharacterized protein of 343 aas and 7 TMSs in a 2 + 2 + 3 TMS arrangement.		UP of Anaerolineales bacterium (bioreactor metagenome)

9.A.22.5.5	Uncharacterized protein of 349 aas and 7 TMSs in a 1 + 2 + 2 + 2 TMS arrangement.		UP of Microgenomates group bacterium

9.A.22.5.6	Uncharacterized protein of 375 aas and 6 TMSs in a 2 + 2 + 2 TMS arrangement.		UP of Coriobacteriia bacterium (volcano metagenome)

9.A.22.5.7	Uncharacterized protein of 403 aas and 6 TMSs		UP of Hazenella coriacea

9.A.22.5.8	Uncharacterized protein of 452 aas and 6 or 7 TMSs in a 2 + 2 + 2 or 3 TMS arrangement.		UP of Haloprofundus marisrubri

9.A.22.5.9	Uncharacterized protein of 397 aas and 6 or 7 TMSs in a 2 + 2 + 2 or 3 TMS arrangement.		UP of Leptospiraceae bacterium (activated sludge metagenome)