Structure of a bacterial multidrug ABC transporter

Dawson, Roger; Locher, Kaspar P.

doi:10.1038/nature05155

Cited by 1,211 publications

(1,613 citation statements)

References 44 publications

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“…These data are in striking contrast to the previously published type I ABC transporter crystal structures and biochemical data that showed the existence of wide‐open inward and outward conformations (Dawson & Locher, 2006; Borbat et al , 2007; Ward et al , 2007). In order to identify the mechanism that results in an outward‐open McjD, we performed PELDOR measurements on McjD reconstituted in bicelles with spin‐labelled L52C mutants, at the periplasmic side.…”

Section: Discussioncontrasting

confidence: 99%

“…Under all tested conditions, L52R1 revealed a distance distribution that fits the occluded conformation observed in the crystal structures. It is commonly thought that homodimeric multi‐drug ABC transporters adopt an outward‐open conformation upon nucleotide binding (Dawson & Locher, 2006; Ward et al , 2007). In contrast, heterodimeric ABC exporters assume this outward‐open conformation upon ATP hydrolysis (in the form of ADP‐VO 4 ; Mishra et al , 2014).…”

Section: Discussionmentioning

confidence: 99%

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Structural basis for antibacterial peptide self‐immunity by the bacterial ABC transporter McjD

et al. 2017

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Certain pathogenic bacteria produce and release toxic peptides to ensure either nutrient availability or evasion from the immune system. These peptides are also toxic to the producing bacteria that utilize dedicated ABC transporters to provide self‐immunity. The ABC transporter McjD exports the antibacterial peptide MccJ25 in Escherichia coli. Our previously determined McjD structure provided some mechanistic insights into antibacterial peptide efflux. In this study, we have determined its structure in a novel conformation, apo inward‐occluded and a new nucleotide‐bound state, high‐energy outward‐occluded intermediate state, with a defined ligand binding cavity. Predictive cysteine cross‐linking in E. coli membranes and PELDOR measurements along the transport cycle indicate that McjD does not undergo major conformational changes as previously proposed for multi‐drug ABC exporters. Combined with transport assays and molecular dynamics simulations, we propose a novel mechanism for toxic peptide ABC exporters that only requires the transient opening of the cavity for release of the peptide. We propose that shielding of the cavity ensures that the transporter is available to export the newly synthesized peptides, preventing toxic‐level build‐up.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Structural basis for antibacterial peptide self‐immunity by the bacterial ABC transporter McjD

et al. 2017

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“…From the viewpoint of structures, ABC transporters that utilize the alternating access mechanism are believed to undergo large conformational changes upon ATP binding and hydrolysis (Dawson & Locher, 2006; Ward et al , 2007), whereas McjD so far appeared to be more “rigid” (Bountra et al , 2017). So far, our only evidence that McjD adopts an outward‐open conformation was from transport data using a cross‐linked TMD between TMs1‐2 and TMs1′‐2′ (Bountra et al , 2017).…”

Section: Discussion and Outlookmentioning

confidence: 99%

“…All ABC transporters share a common architecture consisting of a transmembrane domain (TMD) for substrate recognition and transport, and a nucleotide‐binding domain (NBD) that converts the chemical energy of ATP into conformational changes for transport (Beis, 2015). The structures of several homodimeric (Dawson & Locher, 2006; Ward et al , 2007; Perez et al , 2015) and heterodimeric ABC transporters (Hohl et al , 2012; Noll et al , 2017) revealed distinct conformations and suggest, in combination with biophysical studies (e.g., EPR and NMR; Dong et al , 2005; Zou et al , 2009; Bountra et al , 2017; Timachi et al , 2017; Barth et al , 2018), that they undergo large conformational changes during transport. Their complex architecture is, however, a fundamental hurdle to fully understand the coupling between conformational changes, substrate binding, ATP binding and hydrolysis, and transport.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the available structural, biophysical, and biochemical data for exporters, two transport mechanisms have been proposed, the alternating access mechanism (Dawson & Locher, 2006; Ward et al , 2007; Choudhury et al , 2014; Bountra et al , 2017) and the outward‐only mechanism (Perez et al , 2015). ABC exporters that use the alternating access mechanism switch between inward‐ and outward‐facing states with transmembrane helices intertwining, which exposes the ligand binding site alternatively to the inside or outside of the membrane, a process that is believed to be coupled to ATP binding to hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

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Conformational dynamics of the ABC transporter McjD seen by single‐molecule FRET

et al. 2018

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ABC transporters utilize ATP for export processes to provide cellular resistance against toxins, antibiotics, and harmful metabolites in eukaryotes and prokaryotes. Based on static structure snapshots, it is believed that they use an alternating access mechanism, which couples conformational changes to ATP binding (outward‐open conformation) and hydrolysis (inward‐open) for unidirectional transport driven by ATP. Here, we analyzed the conformational states and dynamics of the antibacterial peptide exporter McjD from Escherichia coli using single‐molecule Förster resonance energy transfer (smFRET). For the first time, we established smFRET for an ABC exporter in a native‐like lipid environment and directly monitor conformational dynamics in both the transmembrane‐ (TMD) and nucleotide‐binding domains (NBD). With this, we unravel the ligand dependences that drive conformational changes in both domains. Furthermore, we observe intrinsic conformational dynamics in the absence of ATP and ligand in the NBDs. ATP binding and hydrolysis on the other hand can be observed via NBD conformational dynamics. We believe that the progress made here in combination with future studies will facilitate full understanding of ABC transport cycles.

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Antibiotic Resistance: Mechanisms and Impact

Puglia

Gualerzi

2017

Kirk-Othmer Encyclopedia of Chemical Technology

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Bacterial multidrug resistance poses an enormous threat to the health of mankind and risks to push back the clock of human medicine to the preantibiotic era, when bacterial infections (eg, tuberculosis, syphilis, and staphylococcal infections of wounds) were almost untreatable and resulted in a huge death toll. Bacterial antibiotic resistance (AR) may be conferred by a plethora of mechanisms that can be grouped into three categories: (a) Modification or protection of the antibiotic target—This can occur (i) as a result of one or more mutations of the gene encoding the target (eg, fluoroquinolones resistance due to mutations of topoisomerase II); (ii) following an enzymatic process that chemically modifies structure and properties of the target (eg, macrolide resistance due to 23S rRNA methylation); or (iii) the physical removal of the inhibitor from its target (resistance to tetracycline by the intervention of ribosomal protection proteins). (b) Enzymatic inactivation of the antimicrobial drug (e.g. resistance to β‐lactam antibiotics upon hydrolysis of the β‐lactam ring by β‐lactamases). (c) Blocking the entrance of the antibiotic or promoting its extrusion by remodeling of the cellular membrane (eg, resistance to polymixins) or activation of cellular efflux pumps (eg, multidrug resistance). In this article, we review in some depth all these mechanisms of resistance to various types of antibiotics, describe the concerns of the world health organizations, the likely socioeconomical impact that AR will have in the future, and some possible actions that can be taken to cope with this global problem.

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Structure of a bacterial multidrug ABC transporter

Cited by 1,211 publications

References 44 publications

Structural basis for antibacterial peptide self‐immunity by the bacterial ABC transporter McjD

Structural basis for antibacterial peptide self‐immunity by the bacterial ABC transporter McjD

Conformational dynamics of the ABC transporter McjD seen by single‐molecule FRET

Antibiotic Resistance: Mechanisms and Impact

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