LmrCD is a major multidrug resistance transporter in <i>Lactococcus lactis</i>

Lubelski, Jacek; Jong, Anne de; Merkerk, Ronald van; Agustiandari, Herfita; Kuipers, Oscar P.; Kok, Jan; Driessen, Arnold J. M.

doi:10.1111/j.1365-2958.2006.05267.x

Cited by 88 publications

(117 citation statements)

References 51 publications

(87 reference statements)

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“…The ABC transporter LmrCD has previously been shown to be a major determinant of the MDR phenotype in L. lactis (Lubelski et al, 2006). Transcription of lmrCD is controlled by LmrR, a local regulatory repressor whose gene is located upstream of lmrCD (Agustiandari et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…L. lactis readily develops an MDR phenotype upon long-term exposure to structurally unrelated compounds such as daunomycin, Hoechst 33342, ethidium bromide, rhodamine 6G and cholate (Bolhuis et al, 1994;Lubelski et al, 2004;Mazurkiewicz et al, 2004). This MDR phenotype is due to the constitutive expression of the lmrCD genes, which encode a heterodimeric ATP-binding cassette (ABC) MDR transporter that secretes these compounds from the cell (Lubelski et al, 2006). Expression of the lmrCD genes is controlled by a local transcriptional regulator termed LmrR (Agustiandari et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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LmrR-mediated gene regulation of multidrug resistance in Lactococcus lactis

et al. 2011

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Multidrug resistance (MDR) in Lactococcus lactis is due to the expression of the membrane ATP-binding cassette (ABC) transporter LmrCD. In the absence of drugs, the transcriptional regulator LmrR prevents expression of the lmrCD operon by binding to its operator site. Through an autoregulatory mechanism LmrR also suppresses its own expression. Although the lmrR and lmrCD genes have their own promoters, primer extension analysis showed the presence of a long transcript spanning the entire lmrR-lmrCD cluster, in addition to various shorter transcripts harbouring the lmrCD genes only. 'In-gel' Cu-phenanthroline footprinting analysis indicated an extensive interaction between LmrR and the lmrR promoter/operator region. Atomic force microscopy imaging of the binding of LmrR to the control region of lmrR DNA showed severe deformations indicative of DNA wrapping and looping, while LmrR binding to a fragment containing the lmrCD control region induced DNA bending. The results further suggest a drugdependent regulation mechanism in which the lmrCD genes are co-transcribed with lmrR as a polycistronic messenger. This leads to an LmrR-mediated regulation of lmrCD expression that is exerted from two different locations and by distinct regulatory mechanisms.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LmrR-mediated gene regulation of multidrug resistance in Lactococcus lactis

et al. 2011

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“…Both D-loop mutations were additionally introduced into LmrCD (D507A in LmrC and D593A in LmrD), a wellcharacterized TM287/288 homolog from L. lactis sharing a sequence identity of 36% (23,24). When expressing the D507A LmrC consensus site mutant in L. lactis ΔlmrA ΔlmrCD, transport of the dyes Hoechst 33342 and BCECF-AM was found to be severely affected (Fig.…”

Section: Structural Consequences Of Nucleotide Binding At the Degeneratementioning

confidence: 99%

Structural basis for allosteric cross-talk between the asymmetric nucleotide binding sites of a heterodimeric ABC exporter

Höhl

Hürlimann

Böhm

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

109

153

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ATP binding cassette (ABC) transporters mediate vital transport processes in every living cell. ATP hydrolysis, which fuels transport, displays positive cooperativity in numerous ABC transporters. In particular, heterodimeric ABC exporters exhibit pronounced allosteric coupling between a catalytically impaired degenerate site, where nucleotides bind tightly, and a consensus site, at which ATP is hydrolyzed in every transport cycle. Whereas the functional phenomenon of cooperativity is well described, its structural basis remains poorly understood. Here, we present the apo structure of the heterodimeric ABC exporter TM287/288 and compare it to the previously solved structure with adenosine 5′-(β,γ-imido)triphosphate (AMP-PNP) bound at the degenerate site. In contrast to other ABC exporter structures, the nucleotide binding domains (NBDs) of TM287/288 remain in molecular contact even in the absence of nucleotides, and the arrangement of the transmembrane domains (TMDs) is not influenced by AMP-PNP binding, a notion confirmed by double electron-electron resonance (DEER) measurements. Nucleotide binding at the degenerate site results in structural rearrangements, which are transmitted to the consensus site via two D-loops located at the NBD interface. These loops owe their name from a highly conserved aspartate and are directly connected to the catalytically important Walker B motif. The D-loop at the degenerate site ties the NBDs together even in the absence of nucleotides and substitution of its aspartate by alanine is well-tolerated. By contrast, the D-loop of the consensus site is flexible and the aspartate to alanine mutation and conformational restriction by cross-linking strongly reduces ATP hydrolysis and substrate transport.membrane transport | X-ray crystallography | allosteric communication A BC exporters are found in every organism (1, 2). They minimally consist of four domains and exist as homodimers or heterodimers. Two transmembrane domains (TMDs) span the membrane with a total of 12 transmembrane helices and form the substrate permeation pathway by alternating between inward-and outward-oriented states (Fig. S1A). A pair of nucleotide binding domains (NBDs) is connected to the TMDs via coupling helices and drive conformational cycling of the transporter by binding and hydrolysis of ATP, a process which is linked to NBD dimerization and dissociation (3).In their closed state, the NBDs sandwich two ATP molecules at the dimer interface by composite ATP binding sites involving conserved sequence motifs contributed by both subunits (4, 5). The A-loop and Walker A motif of one NBD and the ABC signature motif of the opposite NBD are involved in nucleotide binding. The Walker B glutamate and the switch-loop histidine constitute a catalytic dyad required for ATP hydrolysis (6, 7). In heterodimeric ABC exporters with asymmetric ATP binding sites, these catalytic residues are noncanonical at the degenerate site and ATP is therefore primarily, if not exclusively, hydrolyzed at the consensus site (8). The Q-and D...

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“…If a drug or several drugs are able to increase the expression of a given ABC transporter, it is reasonable to hypothesize that the drug(s) is a substrate for efflux. Also, comparison of gene expression between drug-resistant strains and wild-type strains can be very useful for identifying proteins involved in drug resistance (293).…”

Section: Drug Efflux Pumps In Bacteriamentioning

confidence: 99%

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

Davidson

Dassa

Orelle

et al. 2008

Microbiol Mol Biol Rev

1,168

1,137

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SUMMARY ATP-binding cassette (ABC) systems are universally distributed among living organisms and function in many different aspects of bacterial physiology. ABC transporters are best known for their role in the import of essential nutrients and the export of toxic molecules, but they can also mediate the transport of many other physiological substrates. In a classical transport reaction, two highly conserved ATP-binding domains or subunits couple the binding/hydrolysis of ATP to the translocation of particular substrates across the membrane, through interactions with membrane-spanning domains of the transporter. Variations on this basic theme involve soluble ABC ATP-binding proteins that couple ATP hydrolysis to nontransport processes, such as DNA repair and gene expression regulation. Insights into the structure, function, and mechanism of action of bacterial ABC proteins are reported, based on phylogenetic comparisons as well as classic biochemical and genetic approaches. The availability of an increasing number of high-resolution structures has provided a valuable framework for interpretation of recent studies, and realistic models have been proposed to explain how these fascinating molecular machines use complex dynamic processes to fulfill their numerous biological functions. These advances are also important for elucidating the mechanism of action of eukaryotic ABC proteins, because functional defects in many of them are responsible for severe human inherited diseases.

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LmrCD is a major multidrug resistance transporter in Lactococcus lactis

Cited by 88 publications

References 51 publications

LmrR-mediated gene regulation of multidrug resistance in Lactococcus lactis

LmrR-mediated gene regulation of multidrug resistance in Lactococcus lactis

Structural basis for allosteric cross-talk between the asymmetric nucleotide binding sites of a heterodimeric ABC exporter

Structure, Function, and Evolution of Bacterial ATP-Binding Cassette Systems

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