PortEco logo

PMID:20038594

From EcoliWiki
Jump to: navigation, search

Contents

Citation

Kim, HS, Nagore, D and Nikaido, H (2010) Multidrug efflux pump MdtBC of Escherichia coli is active only as a B2C heterotrimer. J. Bacteriol. 192:1377-86

Abstract

RND (resistance-nodulation-division) family transporters in Gram-negative bacteria frequently pump out a wide range of inhibitors and often contribute to multidrug resistance to antibiotics and biocides. An archetypal RND pump of Escherichia coli, AcrB, is known to exist as a homotrimer, and this construction is essential for drug pumping through the functionally rotating mechanism. MdtBC, however, appears different because two pump genes coexist within a single operon, and genetic deletion data suggest that both pumps must be expressed in order for the drug efflux to occur. We have expressed the corresponding genes, with one of them in a His-tagged form. Copurification of MdtB and MdtC under these conditions showed that they form a complex, with an average stoichiometry of 2:1. Unequivocal evidence that only the trimer containing two B protomers and one C protomer is active was obtained by expressing all possible combinations of B and C in covalently linked forms. Finally, conversion into alanine of the residues, known to form a proton translocation pathway in AcrB, inactivated transport only when made in MdtB, not when made in MdtC, a result suggesting that MdtC plays a different role not directly involved in drug binding and extrusion.

Links

PubMed PMC2820868 Online version:10.1128/JB.01448-09

Keywords

Drug Resistance, Multiple; Escherichia coli/chemistry; Escherichia coli/drug effects; Escherichia coli/metabolism; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/isolation & purification; Escherichia coli Proteins/metabolism; Gene Expression; Humans; Membrane Transport Proteins/chemistry; Membrane Transport Proteins/isolation & purification; Membrane Transport Proteins/metabolism; Multidrug Resistance-Associated Proteins/chemistry; Multidrug Resistance-Associated Proteins/isolation & purification; Multidrug Resistance-Associated Proteins/metabolism; Mutagenesis, Site-Directed; Protein Multimerization

Significance

You can help EcoliWiki by summarizing why this paper is useful

Useful Materials and Methods

You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.

Annotations

Gene product Qualifier GO ID GO term name Evidence Code with/from Aspect Notes Status

EcoliWiki Links

Add links to pages that link here (e.g. gene, product, method pages)

See also

References

See Help:References for how to manage references in EcoliWiki.