Chlorobiphenyl-desleucyl-vancomycin inhibits the transglycosylation process required for peptidoglycan synthesis in bacteria in the absence of dipeptide binding

Abstract

Novel glycopeptide analogs are known that have activity on vancomycin resistant enterococci despite the fact that the primary site for drug interaction, D-ala-D-ala, is replaced with D-ala-D-lactate. The mechanism of action of these compounds may involve dimerization and/or membrane binding, thus enhancing interaction with D-ala-D-lactate, or a direct interaction with the transglycosylase enzymes involved in peptidoglycan polymerization. We evaluated the ability of vancomycin (V), desleucyl-vancomycin (desleucyl-V), chlorobiphenyl-vancomycin (CBP-V), and chlorobiphenyl-desleucyl-vancomycin (CBP-desleucyl-V) to inhibit (a) peptidoglycan synthesis in vitro using UDP-muramyl-pentapeptide and UDP-muramyl-tetrapeptide substrates and (b) growth and peptidoglycan synthesis in vancomycin resistant enterococci. Compared to V or CBP-V, CBP-desleucyl-V retained equivalent potency in these assays, whereas desleucyl-V was inactive. In addition, CBP-desleucyl-V caused accumulation of N-acetylglucosamine-beta-1, 4-MurNAc-pentapeptide-pyrophosphoryl-undecaprenol (lipid II). These data show that CBP-desleucyl-V inhibits peptidoglycan synthesis at the transglycosylation stage in the absence of binding to dipeptide.

Peripheral modifications of [Ψ[CH 2 NH]Tpg 4 ]vancomycin with added synergistic mechanisms of action provide durable and potent antibiotics

“…Thus, this inhibition of bacterial cell wall synthesis is not derived from inhibition of transpeptidase-catalyzed cross-linking derived from D-Ala-D-Ala/D-Ala-D-Lac binding but rather, likely arises from direct inhibition of transglycosylase by the peripherally modified disaccharide. Previous studies of Kahne and coworkers (32,33) and others (30,31,55) have shown such direct inhibition of transglycosylase by 5 and related CBP-bearing analogs. Finally, the potent pocket-modified vancomycin analog 8, containing the peripheral CBP modification, inhibits cell wall synthesis more effectively than 4, lacking the CBP modification and more potently than either 5 or 6, lacking a productive pocket modification.…”

“…Vancomycin is also thought to inhibit the preceding step in the cell wall biosynthesis, the transglycosylasecatalyzed incorporation of lipid intermediate II into the polysaccharide backbone of the bacterial cell wall. In the case of vancomycin, this inhibition also requires D-Ala-D-Ala binding (30)(31)(32)(33). However, it is not yet clear whether this occurs through direct binding of the vancomycin disaccharide to the enzyme active site, because cell wall binding contributes to its localization, or whether this occurs by indirect enzyme inhibition.…”

Structures of Staphylococcus aureus Cell-Wall Complexes with Vancomycin, Eremomycin, and Chloroeremomycin Derivatives by 13C{19F} and 15N{19F} Rotational-Echo Double Resonance

“…aureus cells were grown in 300 ml of defined media (20) containing [1][2][3][4][5][6][7][8][9][10][11][12][13] C]glycine and L-[ε -15 N]lysine. The cells were harvested at OD 660 = 1.0 and were complexed with 6.7 mg (4.0 μmoles) of FPBV, resulting in 66% cell-wall binding-site occupancy (15).…”

“…FPBV is an analog of [ 19 F] oritavancin (Eli Lilly compound LY329332), a chloroeremomycin derivative (9). Both have a hydrophobic fluorophenylbenzyl disaccharide substituent and both show 100-fold increased activity, relative to their parent compounds ( Figure 2, vertical arrows) on standard tests against VRE (10)(11)(12)(13). In addition, the 4-epi-vancosamine attached to the sixth amino-acid backbone position of chloroeremomycin and [ 19 F]oritavancin increases the antimicrobial activity against VRE by 10-fold relative to their non-substituted analogues, vancomycin and FPBV, respectively ( Figure 2, horizontal arrows).…”

Inhibition of Staphylococcus aureus Cell Wall Biosynthesis by Desleucyl-Oritavancin: a Quantitative Peptidoglycan Composition Analysis by Mass Spectrometry

“…1d) (25)(26)(27). Unlike the Edman degradation product of vancomycin, which is devoid of any activity, des-Ori retains potent antimicrobial activities against both vancomycin-susceptible and -resistant pathogens despite the damaged D-Ala-D-Ala binding site (28,29). This activity is mediated by the secondary binding site, which allows des-Ori binding to cross-linked PG in the cell wall (4, 7), as well as increased binding affinity to lipid II that has a pentaglycine bridge attached (30).…”