Genetic Basis for Activity Differences Between Vancomycin and Glycolipid Derivatives of Vancomycin

Eggert, Ulrike; Ruiz, Natividad; Falcone, Brian V.; Branstrom, Arthur; Goldman, Robert C.; Silhavy, Thomas J.; Kahne, Daniel

doi:10.1126/science.1063611

Cited by 126 publications

(119 citation statements)

References 21 publications

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“…Because glycopeptide analogues containing hydrophobic substituents on the vancosamino nitrogen retain activity against vanA strains when the binding pocket is damaged (7, 34 -36), the Williams model cannot explain the activity of these compounds. Therefore, we have proposed that certain glycopeptide analogues have a second mechanism of action that does not involve peptide binding (7,45). In this paper, we have presented kinetic evidence that chlorobiphenyl-vancosamino derivatives of vancomycin can inhibit PBP1b, the major transglycosylase in E. coli, even in the absence of substrate binding.…”

Section: Discussionmentioning

confidence: 95%

Vancomycin analogues active against vanA-resistant strains inhibit bacterial transglycosylase without binding substrate

Chen

Walker

Sun

et al. 2003

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

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140

147

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Bacterial transglycosylases are enzymes that couple the disaccharide subunits of peptidoglycan to form long carbohydrate chains. These enzymes are the target of the pentasaccharide antibiotic moenomycin as well as the proposed target of certain glycopeptides that overcome vancomycin resistance. Because bacterial transglycosylases are difficult enzymes to study, it has not previously been possible to evaluate how moenomycin inhibits them or to determine whether glycopeptide analogues directly target them. We have identified transglycosylase assay conditions that enable kinetic analysis of inhibitors and have examined the inhibition of Escherichia coli penicillin-binding protein 1b (PBP1b) by moenomycin as well as by various glycopeptides. We report that chlorobiphenyl vancomycin analogues that are incapable of binding substrates nevertheless inhibit E. coli PBP1b, which shows that these compounds interact directly with the enzyme. These findings support the hypothesis that chlorobiphenyl vancomycin derivatives overcome vanA resistance by targeting bacterial transglycosylases. We have also found that moenomycin is not competitive with respect to the lipid II substrate of PBP1b, as has long been believed. With the development of suitable methods to evaluate bacterial transglycosylases, it is now possible to probe the mechanism of action of some potentially very important antibiotics.

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Section: Discussionmentioning

confidence: 95%

Vancomycin analogues active against vanA-resistant strains inhibit bacterial transglycosylase without binding substrate

Chen

Walker

Sun

et al. 2003

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

Self Cite

140

147

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“…Third, we focused on those remaining proteins that are predicted to be essential in E. coli because the OM is an essential organelle, and of unknown function-that is, they are encoded by ''y'' genes. (27)(28)(29). In contrast, Bl.…”

Section: Rationalementioning

confidence: 94%

Identification of two inner-membrane proteins required for the transport of lipopolysaccharide to the outer membrane of Escherichia coli

Ruiz

Gronenberg

Kahne

et al. 2008

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

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241

277

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The outer membrane (OM) of most Gram-negative bacteria contains lipopolysaccharide (LPS) in the outer leaflet. LPS, or endotoxin, is a molecule of important biological activities. In the host, LPS elicits a potent immune response, while in the bacterium, it plays a crucial role by establishing a barrier to limit entry of hydrophobic molecules. Before LPS is assembled at the OM, it must be synthesized at the inner membrane (IM) and transported across the aqueous periplasmic compartment. Much is known about the biosynthesis of LPS but, until recently, little was known about its transport and assembly. We applied a reductionist bioinformatic approach that takes advantage of the small size of the proteome of the Gram-negative endosymbiont Blochmannia floridanus to search for novel factors involved in OM biogenesis. This led to the discovery of two essential Escherichia coli IM proteins of unknown function, YjgP and YjgQ, which are required for the transport of LPS to the cell surface. We propose that these two proteins, which we have renamed LptF and LptG, respectively, are the missing transmembrane components of the ABC transporter that, together with LptB, functions to extract LPS from the IM en route to the OM.ABC transporter ͉ bioinformatics ͉ endosymbiont ͉ membrane biogenesis T he hallmark of Gram-negative bacteria is the presence of two extracytoplasmic membranes: the inner and outer membranes. The inner membrane (IM), which surrounds the cytoplasm, is separated from the outer membrane (OM) by an aqueous compartment known as the periplasm (1, 2). The IM is composed of phospholipids, integral transmembrane (TM) proteins that span the IM with ␣-helical TM domains, and lipoproteins (3, 4). In contrast, the OM is typically an asymmetric lipid bilayer where the inner leaflet is composed of phospholipids and the outer leaflet is composed mainly of lipopolysaccharide (LPS) (5). In addition, the OM contains lipoproteins and integral outer membrane proteins (OMPs), most of which span the OM via antiparallel ␤-sheets that fold into ␤-barrels (4, 6). Although some Gram-negative bacteria lack LPS and in others LPS is not essential (7), LPS is essential in Escherichia coli, Salmonella, and probably many other bacteria.In E. coli, the main function of the OM is to serve as a selective permeability barrier against many toxic chemicals, such as detergents and antibiotics (1). Porin proteins in the OM control permeability to hydrophilic molecules, but unlike typical phospholipid bilayers, the OM is quite impermeable to hydrophobic molecules, mainly because of LPS (1). For the OM to serve as a barrier, all OM components must be assembled properly. None of the components of the OM are synthesized in situ, so they must be transported to the OM from their site of synthesis. All OMPs and lipoproteins are made in the cytoplasm and cross the IM through the Sec translocon (3). After their signal sequence is removed, OMPs are thought to travel across the periplasm aided by chaperones that deliver them to the OM Bam complex (␤-barrel a...

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“…These results indicate two possibilities; one is that the factors, which exhibit the moenomycin binding, but have no TGase consensus region, are present in S. aureus, and those are associated with moenomycin-resistance and/or vancomycin-intermediate susceptibility; the second is that factors other than moenomycin-binding proteins also affect the moeno- mycin-and/or vancomycin-susceptibility. It has been reported that vancomycin-derived modified carbohydrates inhibited the peptidoglycan biosynthesis without binding D-Ala-D-Ala molecules, and inhibited the transglycosylase activity in in vitro experiments (9,12). E. coli mutants showing resistance to these vancomycinderivatives also exhibited the moenomycin-resistance.…”

Section: Discussionmentioning

confidence: 99%

Moenomycin‐Resistance Is Associated with Vancomycin‐Intermediate Susceptibility in Staphylococcus aureus

Nishi

Komatsuzawa

Yamada

et al. 2003

Microbiology and Immunology

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We have previously isolated a vancomycin‐intermediate susceptibility mutant from methicillin‐resistant Staphylococcus aureus (MRSA) strain COL, and demonstrated the increased glycan‐chain length and the decreased moenomycin‐susceptibility. To further investigate the relationship between the resistance to vancomycin and to moenomycin, we isolated moenomycin‐resistant mutants (4–16 fold higher compared to the parent) from 5 MRSA and 2 methicillin‐sensitive S. aureus (MSSA) strains. The MRSA mutants showed a decreased susceptibility to vancomycin (2–4 fold), teicoplanin (2–4 fold) and an increased susceptibility to methicillin (2–8 fold). MSSA strains also showed similar results with those of MRSA strains except that there was no alteration of methicillin susceptibility. Among the mutants, three mutants including two MRSA mutants and one MSSA mutant were analyzed by electron microscopy, and they showed thickened cell walls compared to those of the parents. The glycan‐chain length of the peptidoglycan of the mutant was shown to be slightly longer than that of the parent, but the muropeptide profile was very similar. The expression levels of all PBPs were similar to those of the parent. Furthermore, the nucleotide sequences of sgtA, sgtB and pbp2 in the mutant were identical to those of the parent. These results indicate that the moenomycin‐resistance is closely associated with vancomycin‐intermediate susceptibility in S. aureus.

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Genetic Basis for Activity Differences Between Vancomycin and Glycolipid Derivatives of Vancomycin

Cited by 126 publications

References 21 publications

Vancomycin analogues active against vanA-resistant strains inhibit bacterial transglycosylase without binding substrate

Vancomycin analogues active against vanA-resistant strains inhibit bacterial transglycosylase without binding substrate

Identification of two inner-membrane proteins required for the transport of lipopolysaccharide to the outer membrane of Escherichia coli

Moenomycin‐Resistance Is Associated with Vancomycin‐Intermediate Susceptibility in Staphylococcus aureus

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