Crystal structure of tripartite-type ABC transporter MacB from Acinetobacter baumannii

• Published in: Nature communications Vol. 8; no. 1; pp. 1336 - 11
• Main Authors: Okada, Ui, Yamashita, Eiki, Neuberger, Arthur, Morimoto, Mayu, van Veen, Hendrik W., Murakami, Satoshi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.11.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 631/45/612/1237; 631/535/1266; ABC transporter; ABC transporters; Acinetobacter baumannii - drug effects; Acinetobacter baumannii - genetics; Acinetobacter baumannii - metabolism; Adenosine triphosphatase; Adenosine triphosphate; Amino Acid Sequence; Antibiotics; ATP-Binding Cassette Transporters - chemistry; ATP-Binding Cassette Transporters - genetics; ATP-Binding Cassette Transporters - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Binding; Conserved Sequence; Crystal structure; Crystallography, X-Ray; Drug Resistance, Multiple, Bacterial; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - metabolism; Fusion protein; Helices; Humanities and Social Sciences; Macrolide antibiotics; Membrane fusion; Membrane proteins; Microorganisms; Models, Molecular; Molecular structure; multidisciplinary; Peptides; Periplasm; Protein Domains; Protein Structure, Quaternary; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Science; Science (multidisciplinary); Sequence Homology, Amino Acid; Substrates; Virulence; Virulence factors
• DOI: 10.1038/s41467-017-01399-2
• ISSN: 2041-1723

The MacA–MacB–TolC tripartite complex is a transmembrane machine that spans both plasma membrane and outer membrane and actively extrudes substrates, including macrolide antibiotics, virulence factors, peptides and cell envelope precursors. These transport activities are driven by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. Here, we present the crystal structure of MacB at 3.4-Å resolution. MacB forms a dimer in which each protomer contains a nucleotide-binding domain and four transmembrane helices that protrude in the periplasm into a binding domain for interaction with the membrane fusion protein MacA. MacB represents an ABC transporter in pathogenic microorganisms with unique structural features. The tripartite multidrug efflux pump MacA-MacB-TolC in Gram-negative bacterial pathogens is driven by the ATPase MacB, which belongs to the ATP-binding cassette (ABC) superfamily. Here the authors present the 3.4 Å resolution crystal structure of MacB, and compare it with other known ABC transporter structures.