Protein C (OprC) of the outer membrane of Pseudomonas aeruginosa is a copper-regulated channel protein

Hiroshi Yoneyama, Taiji Nakae

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Protein C (OprC) of the outer membrane of Pseudomonas aeruginosa forms small channels, as assayed by the liposome swelling method. We report here that OprC functions as a channel-forming and copper-binding protein. OprC purified to homogeneity formed a channel in planar lipid bilayers with an ion conductance of about 200 pS in 1 M NaCl. Cloning and sequencing of the gene encoding OprC revealed that it specified a polypeptide comprising 723 and 668 amino acid residues for the precursor and mature polypeptides (M(r) 73,372), respectively. The amino acid sequence of OprC showed the highest degree of similarity with that of NosA of Pseudomonas stutzeri (65% sequence identity) which conveys Cu2+ to intracellular acceptor(s). OprC showed high copper-binding activity (K(d) = 2.6 μM) in aqueous solution containing surfactant. The expression of OprC appeared to be repressed by exogenous Cu2+ and derepressed by anaerobiosis in the presence of nitrate. These results suggest that OprC might be involved in copper utilization.

Original languageEnglish
Pages (from-to)2137-2144
Number of pages8
JournalMicrobiology
Volume142
Issue number8
DOIs
Publication statusPublished - 1996 Aug
Externally publishedYes

Keywords

  • Copper-binding protein
  • Outer membrane
  • Porin
  • Protein C (OprC)
  • Pseudomonas aeruginosa

ASJC Scopus subject areas

  • Microbiology

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