Tellurium ion resistance

The Tellurium Ion Resistance (TerC) Family (TC# 2.A.109) is part of the Lysine Exporter (LysE) Superfamily. A representative list of proteins belonging to the TerC family can be found in the Transporter Classification Database.^[1]

TerC

The TerC family (Pfam 03741) includes the E. coli TerC protein (TC# 2.A.109.1.1) which has been implicated in tellurium resistance.^[2] It is hypothesized to catalyze efflux of tellurium ions.^[2][3] TerC is encoded by plasmid pTE53 from a clinical isolate of E. coli. It has 346 amino acyl residues (aas) and 9 putative transmembrane segments (TMSs) with a large hydrophilic loop between TMSs 5 and 6.^[2]

A homologue in Arabidopsis thaliana (TC# 9.A.30.2.1) may function in prothylakoid membrane biogenises during early chloroplast development.^[4] It has 384 aas and 7-8 putative TMSs. In E. coli, TerC forms a membrane complex with TerB as well as DctA, PspA, HslU, and RplK. The TerB/TerC complex may link different functional modules with biochemical activities of C4-dicarboxylate transport, inner membrane stress response (phage shock protein regulatory complex), ATPase/chaperone activity, and proteosynthesis.^[5] It may be part of a metal sensing stress response system.^[6] The co-presence of TerC and TerE but not TerF correlates with tellurite resistance when several hundred bacterial strains were assayed.^[7]

Function

The reaction proposed to be catalyzed by TerC is:

tellurium ions (in) → tellurium ions (out).

See also

• Tellurium
• Isotopes of tellurium
• Efflux (microbiology)

Further reading

• Taylor, D. E. (1999). "Bacterial tellurite resistance". Trends in Microbiology. 7 (3): 111–115. doi:10.1016/s0966-842x(99)01454-7. PMID 10203839.
• Kazanov, M.D.; Vitreschak, A.G.; Gelfand, M.S. (2007). "Abundance and functional diversity of riboswitches in microbial communities". BMC Genomics. 8: 347. doi:10.1186/1471-2164-8-347. PMC 2211319. PMID 17908319.
• Kwon, K.C.; Cho, M.H. (2008). "Deletion of the chloroplast-localized AtTerC gene product in Arabidopsis thaliana leads to loss of the thylakoid membrane and to seedling lethality". Plant J. 55 (3): 428–442. doi:10.1111/j.1365-313X.2008.03523.x. PMID 18429937.
• Meyer, M.M.; Hammond, M.C.; Salinas, Y.; Roth, A.; Sudarsan, N.; Breaker, R.R. (2011). "Challenges of ligand identification for riboswitch candidates". RNA Biol. 8 (1): 5–10. doi:10.4161/rna.8.1.13865. PMC 3142362. PMID 21317561.