2.A.109 The Tellurium Ion Resistance (TerC) Family

The TerC family (Pfam 03741) includes the E. coli TerC protein which has been implicated in tellurium resistance (Burian et al. 1998). It is hypothesized to catalyze efflux of tellurium ions (Burian et al., 1998; Kormutakova et al. 2000). TerC is encoded by plasmid pTE53 from a clinical isolate of E. coli (Burian et al., 1998). It has 346 aas and 9 putative TMSs with a large hydrophilic loop between TMSs 5 and 6. A homologue in Arabidopsis thaliana (TC# 9.A.30.2.1) may function in prothylakoid membrane biogenises during early chloroplast development (Kwon and Cho 2008). 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 (Turkovicova et al. 2016). It may be part of a metal sensing stress response system (Anantharaman et al. 2012). The co-presence of TerC and TerE but not TerF correlates with tellurite resistance when several hundred bacterial strains were assayed (Orth et al. 2007). Some of these proteins have C-terminal CBS domains.

The reaction proposed to be catalyzed by TerC is:

Tellurium ions (in) → tellurium ions (out)