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Tripropeptin C blocks the lipid cycle of cell wall biosynthesis by complex formation with undecaprenyl pyrophosphate.

ABSTRACT: Tripropeptin C (TPPC) is a naturally occurring cyclic lipodepsipeptide antibiotic produced by a Lysobacter sp. TPPC exhibits potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and penicillin-resistant Streptococcus pneumoniae. This antibiotic also inhibits the incorporation of N-acetylglucosamine into the peptidoglycan of S. aureus at a 50% inhibitory concentration (IC(50)) of 0.7 ?M, which is proportional to its MIC (0.87 ?M; equivalent to 1.0 ?g/ml). Treatment of exponential-phase S. aureus cells with TPPC resulted in accumulation of UDP-MurNAc-pentapeptide in the cytoplasm. The antimicrobial activity of TPPC was weakened by the addition of prenyl pyrophosphates but not by prenyl phosphates, UDP-linked sugars, or the pentapeptide of peptidoglycan. The direct interaction between TPPC and undecaprenyl pyrophosphate (C(55)-PP) was observed by mass spectrometry and thin-layer chromatography analysis, indicating that TPPC can potentially inhibit C(55)-PP phosphatase activity, which plays a crucial role in the lipid cycle of peptidoglycan synthesis. As expected, TPPC inhibits this enzymatic reaction at an IC(50) of 0.03 to 0.1 ?M in vitro, as does bacitracin. From the analysis of accumulation of lipid carrier-related compounds, TPPC was found to cause the accumulation of C(55)-PP in situ, leading to the accumulation of a glycine-containing lipid intermediate. This suggested that the TPPC/C(55)-PP complex also inhibits the transglycosylation step or flippase activity, adding to the inhibition of C(55)-PP dephosphorylation. This mode of action is different from that of currently available drugs such as vancomycin, daptomycin, and bacitracin.

SUBMITTER: Hashizume H

PROVIDER: S-EPMC3147643 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Tripropeptin C blocks the lipid cycle of cell wall biosynthesis by complex formation with undecaprenyl pyrophosphate.

Hashizume Hideki H Sawa Ryuichi R Harada Shigeko S Igarashi Masayuki M Adachi Hayamitsu H Nishimura Yoshio Y Nomoto Akio A

Antimicrobial agents and chemotherapy 20110531 8

Tripropeptin C (TPPC) is a naturally occurring cyclic lipodepsipeptide antibiotic produced by a Lysobacter sp. TPPC exhibits potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and penicillin-resistant Streptococcus pneumoniae. This antibiotic also inhibits the incorporation of N-acetylglucosamine into the peptidoglycan of S. aureus at a 50% inhibitory concentration (IC(50)) of 0.7 μM, which is proportional to its MIC ...[more]

PMID: 21628543

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Project description:The integrity of the bacterial cell envelope is essential to sustain life by countering the high turgor pressure of the cell and providing a barrier against chemical insults. In Bacillus subtilis, synthesis of both peptidoglycan and wall teichoic acids requires a common C55 lipid carrier, undecaprenyl-pyrophosphate (UPP), to ferry precursors across the cytoplasmic membrane. The synthesis and recycling of UPP requires a phosphatase to generate the monophosphate form Und-P, which is the substrate for peptidoglycan and wall teichoic acid synthases. Using an optimized clustered regularly interspaced short palindromic repeat (CRISPR) system with catalytically inactive ("dead") CRISPR-associated protein 9 (dCas9)-based transcriptional repression system (CRISPR interference [CRISPRi]), we demonstrate that B. subtilis requires either of two UPP phosphatases, UppP or BcrC, for viability. We show that a third predicted lipid phosphatase (YodM), with homology to diacylglycerol pyrophosphatases, can also support growth when overexpressed. Depletion of UPP phosphatase activity leads to morphological defects consistent with a failure of cell envelope synthesis and strongly activates the ?M-dependent cell envelope stress response, including bcrC, which encodes one of the two UPP phosphatases. These results highlight the utility of an optimized CRISPRi system for the investigation of synthetic lethal gene pairs, clarify the nature of the B. subtilis UPP-Pase enzymes, and provide further evidence linking the ?M regulon to cell envelope homeostasis pathways.The emergence of antibiotic resistance among bacterial pathogens is of critical concern and motivates efforts to develop new therapeutics and increase the utility of those already in use. The lipid II cycle is one of the most frequently targeted processes for antibiotics and has been intensively studied. Despite these efforts, some steps have remained poorly defined, partly due to genetic redundancy. CRISPRi provides a powerful tool to investigate the functions of essential genes and sets of genes. Here, we used an optimized CRISPRi system to demonstrate functional redundancy of two UPP phosphatases that are required for the conversion of the initially synthesized UPP lipid carrier to Und-P, the substrate for the synthesis of the initial lipid-linked precursors in peptidoglycan and wall teichoic acid synthesis.

Dataset Information

Tripropeptin C blocks the lipid cycle of cell wall biosynthesis by complex formation with undecaprenyl pyrophosphate.

Publications

Tripropeptin C blocks the lipid cycle of cell wall biosynthesis by complex formation with undecaprenyl pyrophosphate.

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