2.A.119  The Organo-Arsenical Exporter (ArsP) Family

 In 2014, the first member of the Duf318 family was functionally characterized (Shen et al. 2014). Most are annotated as 'putative permease' or 'permease'. Many members have 8 putative TMSs with two 4 TMS halves separated by a hydrophilic loop of variable sizes. The two halves arose by an intragenic duplication event. Members of the family appear to be restricted to prokaryotes, both bacteria and archaea. Some members are encoded by genes in operons concerned with arsenate/arsenite resistance (Castillo and Saier, 2010). 

Campylobacter jejuni, a major foodborne pathogen causing gastroenteritis in humans, is prevalent in poultry and is resistant to the organic arsenic compound, roxarsone (4-hydroxy-3-nitrobenzenearsonic acid), which has been used as a feed additive in the poultry industry for growth promotion. Shen et al. (2014) showed that ArsP contributes to organic arsenic resistance in Campylobacter. Analysis of multiple C. jejuni isolates from various animal species revealed that the presence of an intact arsP gene is associated with elevated resistance to roxarsone. In addition, inactivation of arsP in C. jejuni resulted in a 4-fold reduction in the MICs of roxarsone and nitarsone compared to the wild-type strain. Furthermore, cloning of arsP into a C. jejuni strain lacking a functional arsP led to 8- and 64-fold increases in the MICs of roxarsone and nitarsone, respectively. Neither mutation nor overexpression of arsP affected the MICs of inorganic arsenic including arsenite and arsenate. Moreover, acquisition of the arsP gene in NCTC 11168 accumulated less roxarsone than the wild type strain lacking the arsP gene. These results indicated that ArsP functions as an efflux transporter for extrusion of organic arsenic and contributes to resistance to these compounds in C. jejuni (Shen et al. 2014). 

The generalized reaction catalyzed by ArsP is:

Organic arsenic compounds (in) → Organic arsenic compounds (out) 

This family belongs to the Transporter-Opsin-G protein-coupled receptor (TOG) Superfamily.



Castillo, R. and M.H. Saier. (2010). Functional Promiscuity of Homologues of the Bacterial ArsA ATPases. Int J Microbiol 2010: 187373.

Deutschbauer, A., M.N. Price, K.M. Wetmore, W. Shao, J.K. Baumohl, Z. Xu, M. Nguyen, R. Tamse, R.W. Davis, and A.P. Arkin. (2011). Evidence-based annotation of gene function in Shewanella oneidensis MR-1 using genome-wide fitness profiling across 121 conditions. PLoS Genet 7: e1002385.

Shen Z., Luangtongkum T., Qiang Z., Jeon B., Wang L. and Zhang Q. (201). Identification of a novel membrane transporter mediating resistance to organic arsenic in Campylobacter jejuni. Antimicrob Agents Chemother. 58(4):2021-9.

Wang, L., B. Jeon, O. Sahin, and Q. Zhang. (2009). Identification of an arsenic resistance and arsenic-sensing system in Campylobacter jejuni. Appl. Environ. Microbiol. 75: 5064-5073.


TC#NameOrganismal TypeExample

The 8 TMS ArsP protein (Wang et al. 2009Castillo and Saier 2010).  Exports organo-arsenicals such as roxarsone and nitrarsone (Shen et al. 2014).


ArsP of Campylobacter jejuni (B5LWZ8)


The putative 9 or 10 TMS TrkA-C domain protein; DUF318.


TrkA-C domain protein of Bacillus selenitireducens (A8VTI4)


The putative 8 TMS MmarC7_1204 protein


The MmarC7_1204 protein of Methanococcus maripaludis (A6VIJ1)


Uncharacterized protein of 297 aas and 8 TMSs in a 4 + 4 arrangement.

UP of Xenorhabdus budapestensis


Uncharacterized protein of 8 TMSs in a 4 + 4 arrangement.

UP of Pseudomonas aeruginosa


Zn2+/Cd2+/Cu2+ efflux pump of 491aas and 8 TMSs (Deutschbauer et al. 2011).

Heavy metal exporter of Shewanella oneidensis


TC#NameOrganismal TypeExample

The 8 TMS Clohylem_07038 protein


The Clohylem_07038 protein of Clostridium hylemonae (C0C4M2)


Uncharacterized protein of 316 aas and 8 TMSs.  Designated as a member of the DUF2899 family.


UP of Enterorhabdus caecimuris


Uncharacterized protein of 285 aas with 8 TMSs in a 4 + 4 arrangement.

UP of Collinsella tanakaei


Uncharacterized protein of 369 aas and 8 TMSs in a 4 + 4 arrangement.

UP of Acidaminococcus sp. CAG:917


Uncharacterized protein of 318 aas and 8 TMSs in a 4 + 4 arrangement.

UP of Methanosarcina barkeri


TC#NameOrganismal TypeExample

The DUF2899 protein with 404 aa and 10 putative TMSs in an apparent 2 + 3 + 2 + 3 arrangement.


Vibrio harveyi (A6AW26)


Uncharacterized DUF2899 protein of 280 aas.


UP of Ignavibacterium album


Uncharacterized protein of 419 aas and 10 putative TMSs in a 4 + 2 + 4 TMS arrangement.

UP of Halopelagius longus


Uncharacterized protein of 390 aas and 11 putative TMSs in a 5 + 2 + 4 arrangement.

UP of Pseudoalteromonas lipolytica


Uncharacterized protein of 374 aas and 10 TMSs in a 4 + 2 + 4 TMS arrangement.

UP of Paeniclostridium sordellii


Uncharacterized protein of 296 aas and 11 TMSs in a 2 + 3 + 2 + 4 arrangement.

UP of Grimontia celer


Uncharacterized protein of 392 aas and 12 TMSs in a 3 + 3 + 2 + 3 + 1 arrangement.

UP of Albidovulum xiamenense


Uncharacterized protein of 287 aas and 10 TMSs in a 5 + 5 arrangement.

UP of Candidatus Woesearchaeota archaeon