Crystal structure of Escherichia coli CusC, the outer membrane component of a heavy metal efflux pump.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 21249122.
- Also identified by DOI 10.1371/journal.pone.0015610 and PMC identifier 3017539.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
BACKGROUND: While copper has essential functions as an enzymatic co-factor, excess copper ions are toxic for cells, necessitating mechanisms for regulating its levels. The cusCBFA operon of E. coli encodes a four-component efflux pump dedicated to the extrusion of Cu(I) and Ag(I) ions. METHODOLOGY/PRINCIPAL FINDINGS: We have solved the X-ray crystal structure of CusC, the outer membrane component of the Cus heavy metal efflux pump, to 2.3 Å resolution. The structure has the largest extracellular opening of any outer membrane factor (OMF) protein and suggests, for the first time, the presence of a tri-acylated N-terminal lipid anchor. CONCLUSIONS/SIGNIFICANCE: The CusC protein does not have any obvious features that would make it specific for metal ions, suggesting that the narrow substrate specificity of the pump is provided by other components of the pump, most likely by the inner membrane component CusA.
Medical subject headings
- Escherichia coli
- Escherichia coli Proteins
- Membrane Proteins
- Metals, Heavy