4k34

Publication Abstract from PubMed

Gram-negative bacteria, such as Escherichia coli, frequently utilize tripartite efflux complexes in the RND (resistance-nodulation-cell division) family to expel diverse toxic compounds from the cell. These complexes span both the inner and outer membranes of the bacterium via an alpha-helical, inner membrane transporter; a periplasmic membrane fusion protein; and a beta-barrel, outer membrane channel. One such efflux system, CusCBA, is responsible for extruding biocidal Cu(I) and Ag(I) ions. To remove these toxic ions, the CusC outer membrane channel must form a beta-barrel structural domain, which creates a pore and spans the entire outer membrane. We here report the crystal structures of wild-type CusC, as well as two CusC mutants, suggesting that the first N-terminal cysteine residue plays an important role in protein-membrane interactions and is critical for the insertion of this channel protein into the outer membrane. These structures provide insight into the mechanisms on CusC folding and transmembrane channel formation. It is also found that the interactions between CusC and membrane may be crucial for controlling the opening and closing of this beta-barrel, outer membrane channel.

Crystal Structures of CusC Review Conformational Changes Accompanying Folding and Transmembrane Channel Formation.,Lei HT, Bolla JR, Su CC, Yu EW J Mol Biol. 2013 Oct 4. pii: S0022-2836(13)00626-8. doi:, 10.1016/j.jmb.2013.09.042. PMID:24099674^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.