1.B.76 The Copper Resistance Putative Porin (CopB) Family The CopB family consists of proteins with about 420 aas with a single N-terminal hydrophobic TMS, followed by a hydrophilic region of about 200 residues, followed by a beta structured domain predicted to be an outer membrane beta barrel domain by PRED-TMBB. These proteins show similarity to the C-terminal domain of iron oxidase in TC family 2.A.108.1 (Behlau et al. 2011).
References:
Behlau, F., B.I. Canteros, G.V. Minsavage, J.B. Jones, and J.H. Graham. (2011). Molecular characterization of copper resistance genes from Xanthomonas citri subsp. citri and Xanthomonas alfalfae subsp. citrumelonis. Appl. Environ. Microbiol. 77: 4089-4096.
Cortes, L., A.G. Wedd, and Z. Xiao. (2015). The functional roles of the three copper sites associated with the methionine-rich insert in the multicopper oxidase CueO from E. coli. Metallomics 7: 776-785.
Kataoka, K., H. Kogi, S. Tsujimura, and T. Sakurai. (2013). Modifications of laccase activities of copper efflux oxidase, CueO by synergistic mutations in the first and second coordination spheres of the type I copper center. Biochem. Biophys. Res. Commun. 431: 393-397.
Su, J., L. Deng, L. Huang, S. Guo, F. Liu, and J. He. (2014). Catalytic oxidation of manganese(II) by multicopper oxidase CueO and characterization of the biogenic Mn oxide. Water Res 56: 304-313.
Wijekoon, C.J., T.R. Young, A.G. Wedd, and Z. Xiao. (2015). CopC protein from Pseudomonas fluorescens SBW25 features a conserved novel high-affinity Cu(II) binding site. Inorg Chem 54: 2950-2959.
Williams, C.L., H.M. Neu, Y.A. Alamneh, R.M. Reddinger, A.C. Jacobs, S. Singh, R. Abu-Taleb, S.L.J. Michel, D.V. Zurawski, and D.S. Merrell. (2020). Characterization of Copper Resistance Reveals a Role in Virulence. Front Microbiol 11: 16.
Examples:
TC#	Name	Organismal Type	Example
1.B.76.1.1	Putative outer membrane porin, CopB of 422 aas. It has an N-terminal TMS, followed by a hydrophilic proline/alanine-rich domain and a C-terminal putative 10 β-strand domain. It confers copper resistance (Behlau et al. 2011).	Proteobacteria	PP of Xanthomonas citri

1.B.76.1.2	Copper resistance protein, CopB of 251 aas. It has an N-terminal TMS followed by a putative beta barrel domain of 10 - 12 beta strands. This protein is 95% identical to the ortholog in Acinetobacter baumannii which is involved in copper efflux and virulence (Williams et al. 2020).	Proteobacteria	CopB of Acinetobacter sp.

1.B.76.1.3	Copper resistance protein, PcoB of 224 aas and 12 putative β-strands	Proteobacteria	PcoB of Simiduia agarivorans

1.B.76.1.4	Fusion protein of 799 residues with an N-terminal extracytoplasmic (probably periplasmic) multicopper oxidase (Fet3; TC# 2.A.108) domain (residues 1-550) and a C-terminal putative copper resistance porin domain (residues 610 - 795). It is 50% identical to another fusion protein in Fluoribacter dumoffii of 827 aas (WP_010653677.1).	Proteobacteria	Fusion protein of Legionella drancourtii

1.B.76.1.5	Copper resistance protein in the outer membrane, PcoB of 296 aas and 10 putative β-strands. Required for the copper-inducible expression of copper resistance. Encoded on plasmid pRJ1004 (Silver and Ji 1994).		PcoB of E. coli

1.B.76.1.6	*Copper resistance protein B, CopB of 332 aas and 12 putative β-strands. May function with the copper uptake system, CopCD and the periplasmic CopA protein (TC# 9.B.62.6.1) (Wijekoon et al.* 2015).**		CopCD of Pseudomonas fluorescens

1.B.76.1.8	Blue multi-copper oxidase of 516 aas, CueO. CueO is involved in copper tolerance under aerobic conditions. It features the four typical copper atoms that act as electron transfer (T1) and dioxygen reduction (T2, T3; trinuclear) sites. In addition, it displays a methionine- and histidine-rich insert that includes a helix that blocks physical access to the T1 site (Cortes et al. 2015). It catalyzes oxidation of Mn²⁺ (Su et al. 2014). Also referred to as copper efflux oxidase (Kataoka et al. 2013).		CueO of E. coli