Glycopeptide Antibiotic Activity and the Possible Role of Dimerization: A Model for Biological Signaling

Mackay, Joel P.; Gerhard, Ute; Beauregard, Daniel A.; Williams, Dudley H.; Westwell, Martin S.; Searle, Mark S.

doi:10.1021/ja00090a006

Cited by 211 publications

(218 citation statements)

References 3 publications

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“…These results may have implications for other binding processes which occur near membrane surfaces.Recent reviews of structure-activity relationships for antibiotics of the vancomycin group (10) have not considered dimerization of the antibiotics, which we now believe plays an important role in the mode of action (5,8,9,16). Here, we present results consistent with a mechanism by which dimeric (e.g., vancomycin [Fig.…”

supporting

confidence: 78%

Dimerization and membrane anchors in extracellular targeting of vancomycin group antibiotics

Beauregard¹,

Williams²,

Gwynn³

et al. 1995

Antimicrob Agents Chemother

236

193

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Antibiotics of the vancomycin group are shown to enhance their affinities for the bacterial cell wall by the devices of either dimerization (vancomycin and other glycopeptides which dimerize even more strongly) or use of a membrane anchor (teicoplanin); a chelate mechanism is suggested in both cases, as supported by antagonism experiments with the cell wall analog di-N-acetyl-L-Lys-D-Ala-D-Ala. These results may have implications for other binding processes which occur near membrane surfaces.Recent reviews of structure-activity relationships for antibiotics of the vancomycin group (10) have not considered dimerization of the antibiotics, which we now believe plays an important role in the mode of action (5,8,9,16). Here, we present results consistent with a mechanism by which dimeric (e.g., vancomycin [Fig. 1A]) and lipoylated (e.g., teicoplanin [ Fig. 1C]) glycopeptides enhance the binding affinities to their cellular targets by preferential location of the antibiotic near the site of cell wall biosynthesis.The antibacterial activities of vancomycin antibiotics result from their affinities for the Opeptidyl-D-Ala-D-Ala sequence present in the growing cell wall of gram-positive bacteria (11,14,18); bound antibiotic inhibits the transglycosylase and transpeptidase enzymes responsible for construction of the cell wall (13). While the antibiotic activity can generally be correlated with the association constant for the cell wall, as measured with the cell wall analog di-N-acetyl-L-Lys-D-Ala-D-Ala (DALAA), antibiotics which dimerize strongly show anomalously high in vitro activities (4, 6, 9).Back-to-back homodimers (Fig. 2) are formed by most antibiotics of the vancomycin group (with the exception of teicoplanin [see below]), as shown by nuclear magnetic resonance studies (4,8,16). Dimerization is promoted by structural epitopes which appear as additions to the basic heptapeptide motif, including chlorine atoms and sugars at two sites (8). Furthermore, dimerization increases the affinity for cell wall analogs by a factor of 1 to 10, as shown in nuclear magnetic resonance experiments (9); conversely, cell wall fragments enhance dimerization by factors of 2 to 100 (9).This evidence suggests that dimerization may have physiological significance in the action of antibiotics of the vancomycin group. This was investigated by determining the effects of the cell wall analog DALAA on the potencies of glycopeptide antibiotics exhibiting a range of dimerization constants by an agar diffusion assay by the methods of Rake et al. (12). Glycopeptides (1 g) and DALAA (1 to 200 g) were added as aqueous solutions to paper disks (6-mm diameter; Whatman AA), which were dried before being placed on the surfaces of agar plates (1-mm agar thickness); antibiotic medium 1 (Difco Laboratories, Detroit,) was inoculated with Bacillus subtilis ATCC 6633 (30-l spore suspension/10 ml of agar Difco Laboratories, Detroit, Mich.), which was used as the indicator organism. After incubation at 37ЊC for 18 h, inhibition zone diameters were measured. D...

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supporting

confidence: 78%

Dimerization and membrane anchors in extracellular targeting of vancomycin group antibiotics

Beauregard¹,

Williams²,

Gwynn³

et al. 1995

Antimicrob Agents Chemother

236

193

View full text Add to dashboard Cite

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“…5a). This process, although undetected by adsorbed mass measurements, is relevant in the binding process, because the binding of dimerizing glycopeptides to a transglycosylation site displays a binding constant significantly larger than the related monomeric adhesion, a situation reminiscent of the chelate effect (15). This mechanism is compatible with the geometry of KDADA-1 and the intrinsic mobility of receptors in the self-assembled monolayer on the PnP.…”

Section: Pnp As Probes Of Molecular Interactionsmentioning

confidence: 91%

Light scattered by model phantom bacteria reveals molecular interactions at their surface

Ghetta

Prosperi

Mantegazza

et al. 2005

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

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Testing molecular interactions is an ubiquitous need in modern biology and molecular medicine. Here, we present a qualitative and quantitative method rooted in the basic properties of the scattering of light, enabling detailed measurement of ligandreceptor interactions occurring on the surface of colloids. The key factor is the use of receptor-coated nanospheres matched in refractive index with water and therefore optically undetectable (''phantom'') when not involved in adhesion processes. At the occurrence of ligand binding at the receptor sites, optically unmatched material adsorbs on the nanoparticle surface, giving rise to an increment in their scattering cross section up to a maximum corresponding to saturated binding sites. The analysis of the scattering growth pattern enables extracting the binding affinity. This label-free method has been assessed through the determination of the binding constant of the antibiotic vancomycin with the tripeptide L-Lys-D-Ala-D-Ala and of the vancomycin dimerization constant. We shed light on the role of chelate effect and molecular hindrance in the activity of this glycopeptide.binding affinity ͉ nanoparticles ͉ vancomycin ͉ ligand-receptor recognition T he formation of supramolecular complexes, involving interactions between biologically relevant macromolecules through noncovalent reversible bindings, is one of the most intensely investigated interdisciplinary topics today. Specifically, the evaluation and quantification of lock-and-key molecular interactions is of paramount importance in modern biology and molecular medicine. Traditional UV, mass and NMR spectroscopies, microcalorimetry, and several surface-sensitive techniques (e.g., evanescent wave spectroscopies, ellipsometry, and quartz crystal microbalance technique) allow the investigation of these complex and often cooperative binding events. As each of these techniques provides information on different aspects of the interactions, but not a complete description of the phenomena at play (refs. 1-3 and references therein), there is a continuous exploration for new methodologies capable of detecting and measuring binding affinities. Recent examples exploit the dispersion of colloids, either by detecting the adhesion of sedimented microspheres (4) or inducing interactions or spectral changes in suspensions of nanoparticles (ref. 5 and references therein). Here, we present a tool based on the high sensitivity offered by the measurement of scattered light intensity (I) when the binding occurs on the surface of index-matched colloids.Although broadly used in a large variety of contexts, light scattering has never been applied to measure binding affinities in biomolecular interactions (6). As a matter of fact, binding of insulated ligands and receptors in dilute solutions produces a negligible increment of scattered light, and the use of mesoscopic particles hosting multiple receptors or ligands, including real bacteria, is typically of little help because particles generally scatter too much light compared with the con...

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“…A propensity for dimerization leads to cooperative binding of the target, which increases the activity of the antibiotic (3,13). An exception to this is teicoplanin, which apparently relies on an acyl membrane anchor to provide binding stability (3).…”

mentioning

confidence: 99%

Peptidoglycan synthesis and structure in Staphylococcus haemolyticus expressing increasing levels of resistance to glycopeptide antibiotics

Billot-Klein¹,

Gutmann²,

Bryant³

et al. 1996

J Bacteriol

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The structures of cytoplasmic peptidoglycan precursor and mature peptidoglycan of an isogenic series of Staphylococcus haemolyticus strains expressing increasing levels of resistance to the glycopeptide antibiotics teicoplanin and vancomycin (MICs, 8 to 32 and 4 to 16 g/ml, respectively) were determined. High-performance liquid chromatography, mass spectrometry, amino acid analysis, digestion by R39 D,D-carboxypeptidase, and N-terminal amino acid sequencing were utilized. UDP-muramyl-tetrapeptide-D-lactate constituted 1.7% of total cytoplasmic peptidoglycan precursors in the most resistant strain. It is not clear if this amount of depsipeptide precursor can account for the levels of resistance achieved by this strain. Detailed structural analysis of mature peptidoglycan, examined for the first time for this species, revealed that the peptidoglycan of these strains, like that of other staphylococci, is highly cross-linked and is composed of a lysine muropeptide acceptor containing a substitution at its -amino position of a glycine-containing cross bridge to the D-Ala 4 of the donor, with disaccharide-pentapeptide frequently serving as an acceptor for transpeptidation. The predominant cross bridges were found to be COOH-Gly-Gly-Ser-Gly-Gly-NH 2 and COOH-Ala-Gly-Ser-GlyGly-NH 2 . Liquid chromatography-mass spectrometry analysis of the peptidoglycan of resistant strains revealed polymeric muropeptides bearing cross bridges containing an additional serine in place of glycine (probable structures, COOH-Gly-Ser-Ser-Gly-Gly-NH 2 and COOH-Ala-Gly-Ser-Ser-Gly-NH 2 ). Muropeptides bearing an additional serine in their cross bridges are estimated to account for 13.6% of peptidoglycan analyzed from resistant strains of S. haemolyticus. A soluble glycopeptide target (L-Ala-␥-D-iso-glutamyl-L-Lys-D-Ala-D-Ala) was able to more effectively compete for vancomycin when assayed in the presence of resistant cells than when assayed in the presence of susceptible cells, suggesting that some of the resistance was directed towards the cooperativity of glycopeptide binding to its target. These results are consistent with a hypothesis that alterations at the level of the cross bridge might interfere with the binding of glycopeptide dimers and therefore with the cooperative binding of the antibiotic to its target in situ. Glycopeptide resistance in S. haemolyticus may be multifactorial.

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Glycopeptide Antibiotic Activity and the Possible Role of Dimerization: A Model for Biological Signaling

Cited by 211 publications

References 3 publications

Dimerization and membrane anchors in extracellular targeting of vancomycin group antibiotics

Dimerization and membrane anchors in extracellular targeting of vancomycin group antibiotics

Light scattered by model phantom bacteria reveals molecular interactions at their surface

Peptidoglycan synthesis and structure in Staphylococcus haemolyticus expressing increasing levels of resistance to glycopeptide antibiotics

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