Cadmium resistance transporter

The cadmium resistance (CadD) protein family (TC# 2.A.77) belongs to the Lysine exporter (LysE) superfamily.^[1] CadD members facilitate the export of cationic compounds such as cadmium ions.^[2]

Cadmium Resistance Protein
Identifiers
Symbol	CadD
Pfam	PF03596
InterPro	IPR004676
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Members

Currently, many sequenced proteins comprise the CadD family. Two are close orthologues in two Staphylococcus species that have been reported to function in cadmium resistance, a fourth has been reported to function in quaternary ammonium cation export, and the fourth is a distant open reading frame (ORF) in Staphylococcus aureus.^[3] These proteins are found in Gram-positive bacteria. Their mode of energy coupling has not been investigated, but is hypothesized to include a proton antiport mechanism. This family is distantly related to members of the LysE family (TC #2.A.75) and the RhtB family (TC #2.A.76). These three families, which are included in the LysE superfamily, all consist of proteins of similar sizes (about 200 residues) and topologies (6 putative transmembrane α-helical segments; 5 experimentally determined TMSs).^[4]

General Transport Reaction

The probable reaction catalyzed by these proteins is:^[2]

Cationic compound (in) + nH⁺ (out) → Cationic compound (out) + nH⁺ (in).

Further reading

• Schirawski J, Hagens W, Fitzgerald GF, Van Sinderen D (November 2002). "Molecular characterization of cadmium resistance in Streptococcus thermophilus strain 4134: an example of lateral gene transfer". Applied and Environmental Microbiology. 68 (11): 5508–16. Bibcode:2002ApEnM..68.5508S. doi:10.1128/AEM.68.11.5508-5516.2002. PMC 129935. PMID 12406744.
• Johnson DA, Tetu SG, Phillippy K, Chen J, Ren Q, Paulsen IT (October 2008). "High-throughput phenotypic characterization of Pseudomonas aeruginosa membrane transport genes". PLOS Genetics. 4 (10): e1000211. doi:10.1371/journal.pgen.1000211. PMC 2542419. PMID 18833300.
• Nies DH (January 1992). "Resistance to cadmium, cobalt, zinc, and nickel in microbes". Plasmid. 27 (1): 17–28. doi:10.1016/0147-619X(92)90003-S. PMID 1741458.
• Braz VS, Marques MV (October 2005). "Genes involved in cadmium resistance in Caulobacter crescentus". FEMS Microbiology Letters. 251 (2): 289–95. doi:10.1016/j.femsle.2005.08.013. PMID 16168577.
• Lee SW, Glickmann E, Cooksey DA (April 2001). "Chromosomal locus for cadmium resistance in Pseudomonas putida consisting of a cadmium-transporting ATPase and a MerR family response regulator". Applied and Environmental Microbiology. 67 (4): 1437–44. Bibcode:2001ApEnM..67.1437L. doi:10.1128/AEM.67.4.1437-1444.2001. PMC 92752. PMID 11282588.